test: adjusted ScoringBehavior test

lib/game/components/scoring_behavior.dart

@@ -24,7 +24,7 @@ class ScoringBehavior extends ContactBehavior with HasGameRef<PinballGame> {
 
     gameRef.read<GameBloc>().add(Scored(points: _points));
     gameRef.audio.score();
-    gameRef.firstChild<ZCanvasComponent>()?.add(
+    gameRef.firstChild<ZCanvasComponent>()!.add(
           ScoreText(
             text: _points.toString(),
             position: other.body.position,

test/game/components/scoring_behavior_test.dart

@@ -8,6 +8,7 @@ import 'package:mocktail/mocktail.dart';
 import 'package:pinball/game/game.dart';
 import 'package:pinball_audio/pinball_audio.dart';
 import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_flame/pinball_flame.dart';
 
 import '../../helpers/helpers.dart';
 
@@ -90,7 +91,8 @@ void main() {
           const points = 20;
           final scoringBehavior = ScoringBehavior(points: points);
           await parent.add(scoringBehavior);
-          await game.ensureAdd(parent);
+          final canvas = ZCanvasComponent(children: [parent]);
+          await game.ensureAdd(canvas);
 
           scoringBehavior.beginContact(ball, MockContact());
           await game.ready();