### 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_READ_THREAD_GUARD_V(false);
	if (!initialized) {
		WARN_PRINT_ONCE("Attempting to access theme items too early; prefer NOTIFICATION_POSTINITIALIZE and NOTIFICATION_THEME_CHANGED");
	}
	if (p_theme_type == StringName() || p_theme_type == get_class_name() || p_theme_type == theme_type_variation) {
		if (has_theme_icon_override(p_name)) {
			return true;
		}
	}
	List<StringName> theme_types;
	theme_owner->get_theme_type_dependencies(this, p_theme_type, &theme_types);
	return theme_owner->has_theme_item_in_types(Theme::DATA_TYPE_ICON, p_name, theme_types);
}
bool Window::has_theme_stylebox(const StringName &p_name, const StringName &p_theme_type) const {