Missing translation: "host_modal.crowded" (#3102)

## Description:

Join Lobby Modal will show:
Crowded modifier
Enabled

## 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/lang/en.json

@@ -447,7 +447,8 @@
     "gold_multiplier": "Gold multiplier",
     "gold_multiplier_placeholder": "2.0x",
     "starting_gold": "Starting gold",
-    "starting_gold_placeholder": "5000000"
+    "starting_gold_placeholder": "5000000",
+    "crowded": "Crowded modifier"
   },
   "team_colors": {
     "red": "Red",