refactor: removed unused import

lib/game/pinball_game.dart

@@ -5,7 +5,6 @@ import 'package:flame/components.dart';
 import 'package:flame/input.dart';
 import 'package:flame_bloc/flame_bloc.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';
-import 'package:pinball/flame/flame.dart';
 import 'package:pinball/game/game.dart';
 import 'package:pinball/gen/assets.gen.dart';
 import 'package:pinball_audio/pinball_audio.dart';