### Godot version

4.1 rc3

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description

This™
![image](https://github.com/godotengine/godot/assets/2223172/cb33110f-a5b0-400a-951f-3fa425f05714)

It can still happen, but it's more difficult to trigger.

### Steps to reproduce

1. Create a new scene with a Control node
2. Add Theme to the Control
3. Open Theme Editor
4. Clear the `theme` property in Control
5. Save, with Theme Editor opened
6. Restart

### Minimal reproduction project

N/A
EditorInspector::cleanup_plugins();
	EditorTranslationParser::get_singleton()->clean_parsers();
	ResourceImporterScene::clean_up_importer_plugins();
	remove_print_handler(&print_handler);
	EditorHelp::cleanup_doc();
	memdelete(editor_selection);
	memdelete(editor_plugins_over);
	memdelete(editor_plugins_force_over);
	memdelete(editor_plugins_force_input_forwarding);
	memdelete(progress_hb);
	EditorSettings::destroy();
}
/*
 * EDITOR PLUGIN LIST
 */
void EditorPluginList::make_visible(bool p_visible) {