fix(i18n): correct Irish locale flag and language label

- Fix locale key in lang-list.json from "locale-ie-GA" to "locale-ga-IE"
  to match the actual locale code used in IntlProvider
- Add ga -> ie mapping in getFlagCodeForLocale() so the Ireland flag is
  shown instead of the Gabon flag
- Add missing ["ga", "ga-IE"] entry to check-locales.cjs validation list

Fixes NginxProxyManager/nginx-proxy-manager#5354

frontend/check-locales.cjs

@@ -13,6 +13,7 @@ const allLocales = [
   ["es", "es-ES"],
   ["et", "et-EE"],
   ["fr", "fr-FR"],
+  ["ga", "ga-IE"],
   ["it", "it-IT"],
   ["ja", "ja-JP"],
   ["nl", "nl-NL"],

frontend/src/locale/IntlProvider.tsx

@@ -72,6 +72,7 @@ const getFlagCodeForLocale = (locale?: string) => {
     vi: "vn", // Vietnam
     ko: "kr", // Korea
     cs: "cz", // Czechia
+    ga: "ie", // Ireland (Irish)
   };
 
   if (specialCases[thisLocale]) {

frontend/src/locale/src/lang-list.json

@@ -8,7 +8,7 @@
   "locale-et-EE": {
     "defaultMessage": "Eesti"
   },
-  "locale-ie-GA": {
+  "locale-ga-IE": {
     "defaultMessage": "Gaeilge"
   },
   "locale-de-DE": {