### 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
accept->queue_free();
			}
			if (save_accept) {
				save_accept->queue_free();
			}
			editor_data.save_editor_external_data();
			FileAccess::set_file_close_fail_notify_callback(nullptr);
			log->deinit(); 
			editor_data.clear_edited_scenes();
		} break;
		case NOTIFICATION_READY: {
			{
				_initializing_plugins = true;
				Vector<String> addons;
				if (ProjectSettings::get_singleton()->has_setting("editor_plugins/enabled")) {
					addons = GLOBAL_GET("editor_plugins/enabled");
				}
				for (int i = 0; i < addons.size(); i++) {
					set_addon_plugin_enabled(addons[i], true);
				}
				_initializing_plugins = false;
				if (!pending_addons.is_empty()) {
					EditorFileSystem::get_singleton()->connect("script_classes_updated", callable_mp(this, &EditorNode::_enable_pending_addons));
				}
			}
			RenderingServer::get_singleton()->viewport_set_disable_2d(get_scene_root()->get_viewport_rid(), true);
			RenderingServer::get_singleton()->viewport_set_environment_mode(get_viewport()->get_viewport_rid(), RenderingServer::VIEWPORT_ENVIRONMENT_DISABLED);
			feature_profile_manager->notify_changed();
			_select_default_main_screen_plugin();