### Godot version

4.0.3.stable

### System information

windows 11

### Issue description

fullscreen on the window node is not working and will show up as a windowed.

### Steps to reproduce

disable Embed Subwindows in Project Settings/Display/Window.
create a window node and set its mode to fullscreen.

### Minimal reproduction project

[fullscreen.zip](https://github.com/godotengine/godot/files/11821834/fullscreen.zip)
ERR_MAIN_THREAD_GUARD;
	title = p_title;
	if (embedder) {
		embedder->_sub_window_update(this);
	} else if (window_id != DisplayServer::INVALID_WINDOW_ID) {
		String tr_title = atr(p_title);
#ifdef DEBUG_ENABLED
		if (window_id == DisplayServer::MAIN_WINDOW_ID) {
			
			
			
			tr_title = vformat("%s (DEBUG)", tr_title);
		}
#endif
		DisplayServer::get_singleton()->window_set_title(tr_title, window_id);
	}
}
String Window::get_title() const {