### 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);
	const Ref<Font> *font = theme_font_override.getptr(p_name);
	return font != nullptr;
}
bool Window::has_theme_font_size_override(const StringName &p_name) const {
	ERR_READ_THREAD_GUARD_V(false);
	const int *font_size = theme_font_size_override.getptr(p_name);
	return font_size != nullptr;
}
bool Window::has_theme_color_override(const StringName &p_name) const {
	ERR_READ_THREAD_GUARD_V(false);
	const Color *color = theme_color_override.getptr(p_name);
	return color != nullptr;
}
bool Window::has_theme_constant_override(const StringName &p_name) const {
	ERR_READ_THREAD_GUARD_V(false);
	const int *constant = theme_constant_override.getptr(p_name);
	return constant != nullptr;
}
float Window::get_theme_default_base_scale() const {
	ERR_READ_THREAD_GUARD_V(0);
	return theme_owner->get_theme_default_base_scale();
}
Ref<Font> Window::get_theme_default_font() const {
	ERR_READ_THREAD_GUARD_V(Ref<Font>());
	return theme_owner->get_theme_default_font();
}
int Window::get_theme_default_font_size() const {