chore: move StartGameBloc over the app

lib/app/view/app.dart

@@ -8,6 +8,7 @@ import 'package:leaderboard_repository/leaderboard_repository.dart';
 import 'package:pinball/game/game.dart';
 import 'package:pinball/l10n/l10n.dart';
 import 'package:pinball/select_character/select_character.dart';
+import 'package:pinball/start_game/start_game.dart';
 import 'package:pinball_audio/pinball_audio.dart';
 import 'package:pinball_ui/pinball_ui.dart';
 
@@ -34,8 +35,11 @@ class App extends StatelessWidget {
         RepositoryProvider.value(value: _leaderboardRepository),
         RepositoryProvider.value(value: _pinballAudio),
       ],
-      child: BlocProvider(
+      child: MultiBlocProvider(
-        create: (context) => CharacterThemeCubit(),
+        providers: [
+          BlocProvider(create: (_) => CharacterThemeCubit()),
+          BlocProvider(create: (_) => StartGameBloc()),
+        ],
         child: MaterialApp(
           title: 'I/O Pinball',
           theme: PinballTheme.standard,