### Godot version

2992ffd25523cb8b3e0ef1b873c40115b8940178

### System information

Windows 10

### Issue description

Godot crashes randomly within a few seconds after project start when moving with the mouse.

![win_err](https://github.com/godotengine/godot/assets/52464204/1da28596-d95b-40f3-b32f-12219ec02c5d)

Started after recent merge of https://github.com/godotengine/godot/pull/67791.
I can confirm that reverting the pr fixes the crashes.

### Steps to reproduce

see desc

### Minimal reproduction project

N/A
ERR_READ_THREAD_GUARD_V(Ref<Theme>());
	return theme;
}
void Window::_theme_changed() {
	if (is_inside_tree()) {
		theme_owner->propagate_theme_changed(this, this, true, false);
	}
}
void Window::_notify_theme_override_changed() {
	if (!bulk_theme_override && is_inside_tree()) {
		notification(NOTIFICATION_THEME_CHANGED);
	}
}
void Window::_invalidate_theme_cache() {
	theme_icon_cache.clear();
	theme_style_cache.clear();
	theme_font_cache.clear();
	theme_font_size_cache.clear();
	theme_color_cache.clear();
	theme_constant_cache.clear();
}
void Window::_update_theme_item_cache() {