Add localization for 'not available' message in English and German

lib/l10n/generated/app_localizations.dart

@@ -577,6 +577,12 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Search for groups'**
   String get search_for_groups;
+
+  /// Abbreviation for not available
+  ///
+  /// In en, this message translates to:
+  /// **'Not available'**
+  String get not_available;
 }
 
 class _AppLocalizationsDelegate

lib/l10n/generated/app_localizations_de.dart

@@ -276,4 +276,7 @@ class AppLocalizationsDe extends AppLocalizations {
 
   @override
   String get search_for_groups => 'Nach Gruppen suchen';
+
+  @override
+  String get not_available => 'Nicht verfügbar';
 }

lib/l10n/generated/app_localizations_en.dart

@@ -275,4 +275,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get search_for_groups => 'Search for groups';
+
+  @override
+  String get not_available => 'Not available';
 }