### Godot version

4.0.beta13

### System information

Windows 10

### Issue description

When you call the `seek()` function without a current animation it outputs `Condition "!playback.current.from" is true.` to the debugger.

I was getting the error above whenever I would call `stop()` on an AnimationPlayer when it didn't have a playing animation. I realized that `stop()` also calls the `seek()` function.

I would expect the `seek()` and `stop()` functions to just do nothing, instead of throwing errors, if there isn't a current animation, or at least show an error that says that there is no animation to seek/stop.

This is the same issue that was described here: [#6122](https://github.com/godotengine/godot/issues/6122)

### Steps to reproduce

- Create an AnimationPlayer node.
- Don't have it play any animations.
- Call the `seek()` function.

### Minimal reproduction project

[seek_issue.zip](https://github.com/godotengine/godot/files/10442071/seek_issue.zip)

BlendKey bk;
	bk.from = p_animation1;
	bk.to = p_animation2;
	if (blend_times.has(bk)) {
		return blend_times[bk];
	} else {
		return 0;
	}
}
void AnimationPlayer::queue(const StringName &p_name) {
	if (!is_playing()) {
		play(p_name);
	} else {
		queued.push_back(p_name);
	}
}
Vector<String> AnimationPlayer::get_queue() {
	Vector<String> ret;
	for (const StringName &E : queued) {
		ret.push_back(E);
	}
	return ret;
}
void AnimationPlayer::clear_queue() {
	queued.clear();
}
void AnimationPlayer::play_backwards(const StringName &p_name, double p_custom_blend) {
	play(p_name, p_custom_blend, -1, true);
}
void AnimationPlayer::play(const StringName &p_name, double p_custom_blend, float p_custom_scale, bool p_from_end) {