restrict problematic flags fixes #1690 (#1805)

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.

- [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

regression is found:

evan

src/client/FlagInputModal.ts

@@ -34,9 +34,7 @@ export class FlagInputModal extends LitElement {
           class="flex flex-wrap justify-evenly gap-[1rem] overflow-y-auto overflow-x-hidden h-[90%]"
         >
           ${this.isModalOpen ? 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
@@ -69,6 +67,13 @@ 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;
   }