perf: increase artificial load time and compress pinball_theme assets (#419)

lib/assets_manager/cubit/assets_manager_cubit.dart

@@ -18,7 +18,7 @@ class AssetsManagerCubit extends Cubit<AssetsManagerState> {
     /// delay here, which is a bit random in duration but enough to let the UI
     /// do its job without adding too much delay for the user, we are letting
     /// the UI paint first, and then we start loading the assets.
-    await Future<void>.delayed(const Duration(milliseconds: 300));
+    await Future<void>.delayed(const Duration(seconds: 1));
     emit(
       state.copyWith(
         loadables: [

test/app/view/app_test.dart

@@ -41,7 +41,7 @@ void main() {
           pinballAudioPlayer: pinballAudioPlayer,
         ),
       );
-      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pump(const Duration(milliseconds: 1100));
       expect(find.byType(PinballGamePage), findsOneWidget);
     });
   });