chore(l10n): 清理已移除语言入口文案

lib/l10n/app_localizations_en.dart

@@ -214,9 +214,6 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get preferences => 'Preferences';
 
-  @override
-  String get appLanguage => 'App Language';
-
   @override
   String get followingTab => 'Following';
 
@@ -520,12 +517,6 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get chineseCaptions => 'Chinese captions';
 
-  @override
-  String get language => 'Language';
-
-  @override
-  String get systemLanguage => 'System';
-
   @override
   String get english => 'English';
 
@@ -1252,18 +1243,6 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get searchFailed => 'Search failed. Please try again.';
 
-  @override
-  String get languageFilter => 'Language';
-
-  @override
-  String get languageChinese => 'Chinese';
-
-  @override
-  String get languageIndonesian => 'Indonesian';
-
-  @override
-  String get languageEnglish => 'English';
-
   @override
   String searchResultCount(int count) {
     return '$count results';