### 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
err = platform->export_pack(export_preset, export_defer.debug, export_path);
					}
				} else { 
					String config_error;
					bool missing_templates;
					if (!platform->can_export(export_preset, config_error, missing_templates, export_defer.debug)) {
						ERR_PRINT(vformat("Cannot export project with preset \"%s\" due to configuration errors:\n%s", preset_name, config_error));
						err = missing_templates ? ERR_FILE_NOT_FOUND : ERR_UNCONFIGURED;
					} else {
						platform->clear_messages();
						err = platform->export_project(export_preset, export_defer.debug, export_path);
					}
				}
				if (err != OK) {
					export_error = vformat("Project export for preset \"%s\" failed.", preset_name);
				} else if (platform->get_worst_message_type() >= EditorExportPlatform::EXPORT_MESSAGE_WARNING) {
					export_error = vformat("Project export for preset \"%s\" completed with warnings.", preset_name);
				}
			}
		}
		if (err != OK) {
			ERR_PRINT(export_error);
			_exit_editor(EXIT_FAILURE);
		} else if (!export_error.is_empty()) {
			WARN_PRINT(export_error);
		}
		_exit_editor(EXIT_SUCCESS);
	}
}
void EditorNode::_resources_reimported(const Vector<String> &p_resources) {