### 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)

Playback &c = playback;
	accum_pass++;
	bool seeked = c.seeked; 
	if (p_delta != 0) {
		c.seeked = false;
	}
	float blend = 1.0; 
	List<Blend>::Element *next = NULL;
	for (List<Blend>::Element *E = c.blend.front(); E; E = next) {
		Blend &b = E->get();
		
		
		_animation_process_data(b.data, p_delta, blend, false, false);
		blend = 1.0 - b.blend_left / b.blend_time; 
		b.blend_left -= Math::absf(speed_scale * p_delta);
		next = E->next();
		if (b.blend_left < 0) {
			
			List<Blend>::Element *prev;
			while (E) {
				prev = E->prev();
				c.blend.erase(E);
				E = prev;
			}
		}
	}
	_animation_process_data(c.current, p_delta, blend, seeked, p_started);
}
void AnimationPlayer::_animation_update_transforms() {