Remove manual workaround for missing locales

l10n.yaml

@@ -2,3 +2,4 @@ arb-dir: lib/l10n
 template-arb-file: app_en.arb
 output-localization-file: app_localizations.dart
 nullable-getter: false
+preferred-supported-locales: [ en ]

lib/main.dart

@@ -158,21 +158,6 @@ class MyApp extends StatelessWidget {
           },
           localizationsDelegates: AppLocalizations.localizationsDelegates,
           supportedLocales: AppLocalizations.supportedLocales,
-
-          // Workaround for https://github.com/flutter/flutter/issues/100857
-          localeResolutionCallback: (deviceLocale, supportedLocales) {
-            if (deviceLocale != null) {
-              for (final supportedLocale in supportedLocales) {
-                // Since we currently don't support any country specific locales
-                // such as de-DE and de-AT, it's sufficient to just check it like
-                // this. Otherwise we will need more logic with .countryCode
-                if (supportedLocale.languageCode == deviceLocale.languageCode) {
-                  return supportedLocale;
-                }
-              }
-            }
-            return const Locale('en');
-          },
         ),
       ),
     );