### 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;
	content_scale_mode = p_mode;
	_update_viewport_size();
}
Window::ContentScaleMode Window::get_content_scale_mode() const {
	ERR_READ_THREAD_GUARD_V(CONTENT_SCALE_MODE_DISABLED);
	return content_scale_mode;
}
void Window::set_content_scale_aspect(ContentScaleAspect p_aspect) {
	ERR_MAIN_THREAD_GUARD;
	content_scale_aspect = p_aspect;
	_update_viewport_size();
}
Window::ContentScaleAspect Window::get_content_scale_aspect() const {
	ERR_READ_THREAD_GUARD_V(CONTENT_SCALE_ASPECT_IGNORE);
	return content_scale_aspect;
}
void Window::set_content_scale_factor(real_t p_factor) {
	ERR_MAIN_THREAD_GUARD;
	ERR_FAIL_COND(p_factor <= 0);
	content_scale_factor = p_factor;
	_update_viewport_size();
}
real_t Window::get_content_scale_factor() const {
	ERR_READ_THREAD_GUARD_V(0);
	return content_scale_factor;
}
void Window::set_use_font_oversampling(bool p_oversampling) {