Add localization for chat and repeater features in multiple languages

- Added translations for "Send message", "Guest information", and "Guest tools" in Bulgarian, German, Spanish, French, Hungarian, Italian, Japanese, Korean, Dutch, Polish, Portuguese, Russian, Slovak, Slovenian, Swedish, Ukrainian, and Chinese.
- Updated the "Clock synchronization after login" feature subtitle in all affected languages.
- Removed untranslated keys from the untranslated.json file as they have now been localized.

lib/l10n/app_localizations_ko.dart

@@ -1175,7 +1175,7 @@ class AppLocalizationsKo extends AppLocalizations {
   String get chat_noMessages => '아직 메시지가 없습니다.';
 
   @override
-  String get chat_sendMessage => 'Send message';
+  String get chat_sendMessage => '메시지를 보내기';
 
   @override
   String chat_sendMessageTo(String contactName) {
@@ -1930,16 +1930,16 @@ class AppLocalizationsKo extends AppLocalizations {
   String get room_management => '방 서버 관리';
 
   @override
-  String get repeater_guest => 'Repeater Information';
+  String get repeater_guest => '반복 장비 정보';
 
   @override
-  String get room_guest => 'Room Server Information';
+  String get room_guest => '서버 정보';
 
   @override
   String get repeater_managementTools => '관리 도구';
 
   @override
-  String get repeater_guestTools => 'Guest Tools';
+  String get repeater_guestTools => '손님용 도구';
 
   @override
   String get repeater_status => '상태';