### 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)
if (window_id == DisplayServer::MAIN_WINDOW_ID) {
					RS::get_singleton()->viewport_set_update_mode(get_viewport_rid(), RS::VIEWPORT_UPDATE_DISABLED);
					_update_window_callbacks();
				} else {
					_clear_window();
				}
			} else {
				if (embedder) {
					embedder->_sub_window_remove(this);
					embedder = nullptr;
					RS::get_singleton()->viewport_set_update_mode(get_viewport_rid(), RS::VIEWPORT_UPDATE_DISABLED);
				}
				_update_viewport_size(); 
			}
			RS::get_singleton()->viewport_set_active(get_viewport_rid(), false);
		} break;
	}
}
void Window::set_content_scale_size(const Size2i &p_size) {
	ERR_MAIN_THREAD_GUARD;
	ERR_FAIL_COND(p_size.x < 0);
	ERR_FAIL_COND(p_size.y < 0);
	content_scale_size = p_size;
	_update_viewport_size();
}
Size2i Window::get_content_scale_size() const {
	ERR_READ_THREAD_GUARD_V(Size2i());
	return content_scale_size;
}
void Window::set_content_scale_mode(ContentScaleMode p_mode) {