refactor: revert unintended changes

lib/game/pinball_game.dart

@@ -123,7 +123,7 @@ class DebugPinballGame extends PinballGame with TapDetector {
       anchor: Anchor.center,
     )
       ..position = Vector2(0, -7.8)
-      ..priority = -5;
+      ..priority = -1;
 
     await add(spriteComponent);
   }

lib/gen/assets.gen.dart

@@ -18,10 +18,6 @@ class $AssetsImagesComponentsGen {
   AssetGenImage get background =>
       const AssetGenImage('assets/images/components/background.png');
 
-  /// File path: assets/images/components/flipper.png
-  AssetGenImage get flipper =>
-      const AssetGenImage('assets/images/components/flipper.png');
-
   $AssetsImagesComponentsLaunchRampGen get launchRamp =>
       const $AssetsImagesComponentsLaunchRampGen();
 }