### 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)

String name = p_name;
	if (name == "playback/play") { 
		r_ret = get_current_animation();
	} else if (name.begins_with("libraries")) {
		Dictionary d;
		for (const AnimationLibraryData &lib : animation_libraries) {
			d[lib.name] = lib.library;
		}
		r_ret = d;
	} else if (name.begins_with("next/")) {
		String which = name.get_slicec('/', 1);
		r_ret = animation_get_next(which);
	} else if (name == "blend_times") {
		Vector<BlendKey> keys;
		for (const KeyValue<BlendKey, double> &E : blend_times) {
			keys.ordered_insert(E.key);
		}
		Array array;
		for (int i = 0; i < keys.size(); i++) {
			array.push_back(keys[i].from);
			array.push_back(keys[i].to);
			array.push_back(blend_times.get(keys[i]));
		}
		r_ret = array;
	} else {
		return false;
	}
	return true;
}
void AnimationPlayer::_validate_property(PropertyInfo &p_property) const {