### 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)

ERR_FAIL_COND(p_audio_max_polyphony < 0 || p_audio_max_polyphony > 128);
	audio_max_polyphony = p_audio_max_polyphony;
}
int AnimationPlayer::get_audio_max_polyphony() const {
	return audio_max_polyphony;
}
void AnimationPlayer::set_movie_quit_on_finish_enabled(bool p_enabled) {
	movie_quit_on_finish = p_enabled;
}
bool AnimationPlayer::is_movie_quit_on_finish_enabled() const {
	return movie_quit_on_finish;
}
void AnimationPlayer::_set_process(bool p_process, bool p_force) {
	if (processing == p_process && !p_force) {
		return;
	}
	switch (process_callback) {
		case ANIMATION_PROCESS_PHYSICS:
			set_physics_process_internal(p_process && active);
			break;
		case ANIMATION_PROCESS_IDLE:
			set_process_internal(p_process && active);
			break;
		case ANIMATION_PROCESS_MANUAL:
			break;
	}
	processing = p_process;
}
void AnimationPlayer::_stop_internal(bool p_reset, bool p_keep_state) {