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_zh.dart

@@ -1162,7 +1162,7 @@ class AppLocalizationsZh extends AppLocalizations {
   String get chat_noMessages => '暂无消息';
 
   @override
-  String get chat_sendMessage => 'Send message';
+  String get chat_sendMessage => '发送消息';
 
   @override
   String chat_sendMessageTo(String contactName) {
@@ -1891,16 +1891,16 @@ class AppLocalizationsZh extends AppLocalizations {
   String get room_management => '房间服务器管理';
 
   @override
-  String get repeater_guest => 'Repeater Information';
+  String get repeater_guest => '重复器信息';
 
   @override
-  String get room_guest => 'Room Server Information';
+  String get room_guest => '服务器信息';
 
   @override
   String get repeater_managementTools => '管理工具';
 
   @override
-  String get repeater_guestTools => 'Guest Tools';
+  String get repeater_guestTools => '访客工具';
 
   @override
   String get repeater_status => '状态';