fix: Reset _completeCompleter in ticker

[adil192]

Description

I was running this code:

void attack() async {
  print('Attack started');
  current = PlayerState.attack;

  final attackTicker = animationTicker!;
  await attackTicker.completed;
  print('Attack ticker completed');

  attackTicker.reset();
  current = PlayerState.idle;
}

and attackTicker.completed would get stuck as permanently completed after the first completion.

Checklist

• I have followed the Contributor Guide when preparing my PR.
• I have updated/added tests for ALL new/updated/fixed functionality.
• [-] I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• [-] I have updated/added relevant examples in examples or docs.

Breaking Change?

• [-] Yes, this PR is a breaking change.
• No, this PR is not a breaking change.

Related Issues

The closest issue I can find is #2584 which uses the ticker.onComplete function and ran into a problem because of creating a new ticker. This PR concerns the ticker.completed future.

[spydon]

Thanks for your contribution, only an import fix needed and then it is ready for merge!

[spydon]

Ah, and this test also fails:

  ● SpriteAnimationWidget onComplete callback is called when the animation is finished packages/flame/test/widgets/sprite_animation_widget_test.dart:123:5