restrict problematic flags fixes #1690 (#1805)

## Description:

Some flags are offensive, so don't allow them to be selected by users.

I think it's fine for nations continue to use the flags.

## 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:

evan

src/client/FlagInputModal.ts

@@ -29,9 +29,7 @@ export class FlagInputModal extends LitElement {
           class="flex flex-wrap justify-evenly gap-[1rem] overflow-y-auto overflow-x-hidden h-[90%]"
         >
           ${Countries.filter(
-            (country) =>
-              country.name.toLowerCase().includes(this.search.toLowerCase()) ||
-              country.code.toLowerCase().includes(this.search.toLowerCase()),
+            (country) => !country.restricted && this.includedInSearch(country),
           ).map(
             (country) => html`
               <button
@@ -64,6 +62,13 @@ export class FlagInputModal extends LitElement {
     `;
   }
 
+  private includedInSearch(country: { name: string; code: string }): boolean {
+    return (
+      country.name.toLowerCase().includes(this.search.toLowerCase()) ||
+      country.code.toLowerCase().includes(this.search.toLowerCase())
+    );
+  }
+
   private handleSearch(event: Event) {
     this.search = (event.target as HTMLInputElement).value;
   }

src/client/data/countries.json

@@ -484,7 +484,8 @@
   {
     "code": "Confederate States",
     "continent": "North America",
-    "name": "Confederate States"
+    "name": "Confederate States",
+    "restricted": true
   },
   {
     "code": "1_Connacht",
@@ -702,7 +703,8 @@
   {
     "code": "Fascist Spain",
     "continent": "Europe",
-    "name": "Fascist Spain"
+    "name": "Fascist Spain",
+    "restricted": true
   },
   {
     "code": "fm",
@@ -805,7 +807,8 @@
   {
     "code": "German Empire",
     "continent": "Europe",
-    "name": "German Empire"
+    "name": "German Empire",
+    "restricted": true
   },
   {
     "code": "de",

src/core/Schemas.ts

@@ -190,7 +190,7 @@ export const ID = z
 export const AllPlayersStatsSchema = z.record(ID, PlayerStatsSchema);
 
 export const UsernameSchema = SafeString;
-const countryCodes = countries.map((c) => c.code);
+const countryCodes = countries.filter((c) => !c.restricted).map((c) => c.code);
 export const FlagSchema = z
   .string()
   .max(128)