### 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)
#include "window.h"
#include "core/config/project_settings.h"
#include "core/debugger/engine_debugger.h"
#include "core/input/shortcut.h"
#include "core/string/translation.h"
#include "core/variant/variant_parser.h"
#include "scene/gui/control.h"
#include "scene/scene_string_names.h"
#include "scene/theme/theme_db.h"
#include "scene/theme/theme_owner.h"
bool Window::_set(const StringName &p_name, const Variant &p_value) {
	ERR_MAIN_THREAD_GUARD_V(false);
	String name = p_name;
	if (!name.begins_with("theme_override")) {
		return false;
	}
	if (p_value.get_type() == Variant::NIL || (p_value.get_type() == Variant::OBJECT && (Object *)p_value == nullptr)) {
		if (name.begins_with("theme_override_icons/")) {
			String dname = name.get_slicec('/', 1);