### 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
switch (tool_menu->get_item_id(p_idx)) {
		case TOOLS_ORPHAN_RESOURCES: {
			orphan_resources->show();
		} break;
		case TOOLS_CUSTOM: {
			if (tool_menu->get_item_submenu(p_idx) == "") {
				Callable callback = tool_menu->get_item_metadata(p_idx);
				Callable::CallError ce;
				Variant result;
				callback.callp(nullptr, 0, result, ce);
				if (ce.error != Callable::CallError::CALL_OK) {
					String err = Variant::get_callable_error_text(callback, nullptr, 0, ce);
					ERR_PRINT("Error calling function from tool menu: " + err);
				}
			} 
		} break;
	}
}
void EditorNode::_export_as_menu_option(int p_idx) {