Remove small islands on compact maps with half threshold 🏝️ (#3762)

## Description:

Small-island removal previously ran only on the full-size terrain. The
compact (4x downscaled) map inherited that filtering before being
downscaled, which meant islands that survived at full size could end up
as tiny specks in the compact map.

This PR runs `removeSmallIslands` on the 4x terrain as well, with half
the threshold (15 vs 30 tiles), so very small islands are pruned in
compact maps while the full-size map is unchanged.

## Please complete the following:

- [X] I have added screenshots for all UI updates
- [X] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [X] I have added relevant tests to the test directory
- [X] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

FloPinguin

resources/maps/achiran/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 425,
-    "num_land_tiles": 69861,
+    "num_land_tiles": 69860,
     "width": 500
   },
   "map4x": {
     "height": 850,
-    "num_land_tiles": 284530,
+    "num_land_tiles": 284422,
     "width": 1000
   },
   "name": "Achiran",

resources/maps/aegean/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 500,
-    "num_land_tiles": 68060,
+    "num_land_tiles": 68047,
     "width": 425
   },
   "map4x": {
     "height": 1000,
-    "num_land_tiles": 285421,
+    "num_land_tiles": 284992,
     "width": 850
   },
   "name": "aegean",
@@ -58,8 +58,8 @@
     },
     {
       "coordinates": [1599, 431],
-      "name": "Achaemenid Empire",
-      "flag": "Achaemenid Empire"
+      "flag": "Achaemenid Empire",
+      "name": "Achaemenid Empire"
     },
     {
       "coordinates": [762, 35],
@@ -67,18 +67,18 @@
     },
     {
       "coordinates": [491, 894],
-      "name": "Athens",
-      "flag": "Athens"
+      "flag": "Athens",
+      "name": "Athens"
     },
     {
       "coordinates": [222, 1183],
-      "name": "Sparta",
-      "flag": "Sparta"
+      "flag": "Sparta",
+      "name": "Sparta"
     },
     {
       "coordinates": [446, 104],
-      "name": "Macedonia",
-      "flag": "Macedonia"
+      "flag": "Macedonia",
+      "name": "Macedonia"
     },
     {
       "coordinates": [175, 456],

resources/maps/africa/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 508,
-    "num_land_tiles": 130748,
+    "num_land_tiles": 130741,
     "width": 487
   },
   "map4x": {
     "height": 1016,
-    "num_land_tiles": 537916,
+    "num_land_tiles": 537561,
     "width": 974
   },
   "name": "Africa",

resources/maps/amazonriver/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 69,
-    "num_land_tiles": 69690,
+    "num_land_tiles": 69687,
     "width": 1384
   },
   "map4x": {
     "height": 138,
-    "num_land_tiles": 284707,
+    "num_land_tiles": 284639,
     "width": 2768
   },
   "name": "Amazon River",

resources/maps/antarctica/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 500,
-    "num_land_tiles": 79013,
+    "num_land_tiles": 79002,
     "width": 500
   },
   "map4x": {
     "height": 1000,
-    "num_land_tiles": 320576,
+    "num_land_tiles": 320356,
     "width": 1000
   },
   "name": "antarctica",

resources/maps/archipelagosea/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 377,
-    "num_land_tiles": 9913,
+    "num_land_tiles": 9586,
     "width": 775
   },
   "map4x": {
     "height": 754,
-    "num_land_tiles": 59480,
+    "num_land_tiles": 52779,
     "width": 1550
   },
   "name": "Archipelago Sea",

resources/maps/arctic/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 457,
-    "num_land_tiles": 97929,
+    "num_land_tiles": 97905,
     "width": 457
   },
   "map4x": {
     "height": 914,
-    "num_land_tiles": 409868,
+    "num_land_tiles": 409202,
     "width": 914
   },
   "name": "Arctic",

resources/maps/asia/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 300,
-    "num_land_tiles": 64874,
+    "num_land_tiles": 64855,
     "width": 500
   },
   "map4x": {
     "height": 600,
-    "num_land_tiles": 266262,
+    "num_land_tiles": 265625,
     "width": 1000
   },
   "name": "Asia",

resources/maps/australia/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 375,
-    "num_land_tiles": 81256,
+    "num_land_tiles": 81252,
     "width": 500
   },
   "map4x": {
     "height": 750,
-    "num_land_tiles": 328215,
+    "num_land_tiles": 328153,
     "width": 1000
   },
   "name": "Australia",

resources/maps/baikal/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 391,
-    "num_land_tiles": 133082,
+    "num_land_tiles": 133081,
     "width": 625
   },
   "map4x": {
     "height": 782,
-    "num_land_tiles": 540863,
+    "num_land_tiles": 540826,
     "width": 1250
   },
   "name": "Baikal",

resources/maps/baikalnukewars/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 391,
-    "num_land_tiles": 120323,
+    "num_land_tiles": 120322,
     "width": 625
   },
   "map4x": {
     "height": 782,
-    "num_land_tiles": 488353,
+    "num_land_tiles": 488323,
     "width": 1250
   },
   "name": "Baikal (Nuke Wars)",

resources/maps/beringsea/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 400,
-    "num_land_tiles": 96268,
+    "num_land_tiles": 96248,
     "width": 625
   },
   "map4x": {
     "height": 800,
-    "num_land_tiles": 397269,
+    "num_land_tiles": 396641,
     "width": 1250
   },
   "name": "Bering Sea",

resources/maps/beringstrait/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 229,
-    "num_land_tiles": 35567,
+    "num_land_tiles": 35566,
     "width": 375
   },
   "map4x": {
     "height": 458,
-    "num_land_tiles": 146741,
+    "num_land_tiles": 146676,
     "width": 750
   },
   "name": "BeringStrait",

resources/maps/betweentwoseas/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 265,
-    "num_land_tiles": 88499,
+    "num_land_tiles": 88486,
     "width": 444
   },
   "map4x": {
     "height": 530,
-    "num_land_tiles": 364318,
+    "num_land_tiles": 364078,
     "width": 888
   },
   "name": "BetweenTwoSeas",

resources/maps/blacksea/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 275,
-    "num_land_tiles": 69023,
+    "num_land_tiles": 69017,
     "width": 375
   },
   "map4x": {
     "height": 550,
-    "num_land_tiles": 284219,
+    "num_land_tiles": 284065,
     "width": 750
   },
   "name": "BlackSea",

resources/maps/bosphorusstraits/manifest.json

@@ -11,7 +11,7 @@
   },
   "map4x": {
     "height": 306,
-    "num_land_tiles": 95321,
+    "num_land_tiles": 95304,
     "width": 500
   },
   "name": "Bosphorus Straits",

resources/maps/britannia/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 522,
-    "num_land_tiles": 70124,
+    "num_land_tiles": 70110,
     "width": 400
   },
   "map4x": {
     "height": 1044,
-    "num_land_tiles": 290775,
+    "num_land_tiles": 290479,
     "width": 800
   },
   "name": "Britannia",

resources/maps/britanniaclassic/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 349,
-    "num_land_tiles": 54975,
+    "num_land_tiles": 54968,
     "width": 500
   },
   "map4x": {
     "height": 698,
-    "num_land_tiles": 228849,
+    "num_land_tiles": 228703,
     "width": 1000
   },
   "name": "Britannia Classic",

resources/maps/caucasus/manifest.json

@@ -11,7 +11,7 @@
   },
   "map4x": {
     "height": 500,
-    "num_land_tiles": 209270,
+    "num_land_tiles": 209226,
     "width": 624
   },
   "name": "Caucasus",

resources/maps/conakry/manifest.json

@@ -11,7 +11,7 @@
   },
   "map4x": {
     "height": 500,
-    "num_land_tiles": 272631,
+    "num_land_tiles": 272605,
     "width": 1228
   },
   "name": "Conakry",

resources/maps/deglaciatedantarctica/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 460,
-    "num_land_tiles": 62129,
+    "num_land_tiles": 62082,
     "width": 575
   },
   "map4x": {
     "height": 920,
-    "num_land_tiles": 262417,
+    "num_land_tiles": 261659,
     "width": 1150
   },
   "name": "Deglaciated Antarctica",

resources/maps/didier/manifest.json

@@ -11,7 +11,7 @@
   },
   "map4x": {
     "height": 674,
-    "num_land_tiles": 278359,
+    "num_land_tiles": 278357,
     "width": 750
   },
   "name": "Didier",

resources/maps/didierfrance/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 562,
-    "num_land_tiles": 141151,
+    "num_land_tiles": 141149,
     "width": 525
   },
   "map4x": {
     "height": 1124,
-    "num_land_tiles": 571943,
+    "num_land_tiles": 571849,
     "width": 1050
   },
   "name": "Didier (France)",

resources/maps/dyslexdria/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 336,
-    "num_land_tiles": 108613,
+    "num_land_tiles": 108584,
     "width": 770
   },
   "map4x": {
     "height": 672,
-    "num_land_tiles": 459895,
+    "num_land_tiles": 458859,
     "width": 1540
   },
   "name": "Dyslexdria",

resources/maps/eastasia/manifest.json

@@ -6,12 +6,12 @@
   },
   "map16x": {
     "height": 411,
-    "num_land_tiles": 51660,
+    "num_land_tiles": 51649,
     "width": 390
   },
   "map4x": {
     "height": 822,
-    "num_land_tiles": 215238,
+    "num_land_tiles": 214937,
     "width": 780
   },
   "name": "East Asia",