### 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
if (!scene_path.is_empty()) {
						required_load_paths.push_front(scene_path);
					}
					Ref<SceneState> inherited_state = original_node->get_scene_inherited_state();
					while (inherited_state.is_valid()) {
						String inherited_path = inherited_state->get_path();
						
						if (!inherited_path.is_empty()) {
							required_load_paths.push_front(inherited_path);
						}
						inherited_state = inherited_state->get_base_scene_state();
					}
					
					
					for (String path : required_load_paths) {
						if (!local_scene_cache.find(path)) {
							current_packed_scene = ResourceLoader::load(path, "", ResourceFormatLoader::CACHE_MODE_IGNORE, &err);
							current_packed_scene->set_path(path, true);
							local_scene_cache[path] = current_packed_scene;
						} else {
							current_packed_scene = local_scene_cache[path];
						}
					}
				}
				ERR_FAIL_COND(current_packed_scene.is_null());
				
				Node *instantiated_node = nullptr;
				if (current_packed_scene.is_valid()) {
					instantiated_node = current_packed_scene->instantiate(PackedScene::GEN_EDIT_STATE_INSTANCE);
				}