### 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;
	theme_constant_override[p_name] = p_constant;
	_notify_theme_override_changed();
}
void Window::remove_theme_icon_override(const StringName &p_name) {
	ERR_MAIN_THREAD_GUARD;
	if (theme_icon_override.has(p_name)) {
		theme_icon_override[p_name]->disconnect("changed", callable_mp(this, &Window::_notify_theme_override_changed));
	}
	theme_icon_override.erase(p_name);
	_notify_theme_override_changed();
}
void Window::remove_theme_style_override(const StringName &p_name) {
	ERR_MAIN_THREAD_GUARD;
	if (theme_style_override.has(p_name)) {
		theme_style_override[p_name]->disconnect("changed", callable_mp(this, &Window::_notify_theme_override_changed));
	}
	theme_style_override.erase(p_name);
	_notify_theme_override_changed();
}
void Window::remove_theme_font_override(const StringName &p_name) {
	ERR_MAIN_THREAD_GUARD;
	if (theme_font_override.has(p_name)) {
		theme_font_override[p_name]->disconnect("changed", callable_mp(this, &Window::_notify_theme_override_changed));
	}
	theme_font_override.erase(p_name);
	_notify_theme_override_changed();
}
void Window::remove_theme_font_size_override(const StringName &p_name) {