### 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)

_animation_process(p_time);
}
void AnimationPlayer::_notification(int p_what) {
	switch (p_what) {
		case NOTIFICATION_ENTER_TREE: {
			if (!processing) {
				
				
				set_physics_process_internal(false);
				set_process_internal(false);
			}
			clear_caches();
		} break;
		case NOTIFICATION_READY: {
			if (!Engine::get_singleton()->is_editor_hint() && animation_set.has(autoplay)) {
				play(autoplay);
				_animation_process(0);
			}
		} break;
		case NOTIFICATION_INTERNAL_PROCESS: {
			if (process_callback == ANIMATION_PROCESS_PHYSICS) {
				break;
			}
			if (processing) {
				_animation_process(get_process_delta_time());
			}
		} break;