### Godot version

v4.0.beta17.mono.official [c40020513]

### System information

Window 11, Forward+, GTX 1060

### Issue description

Adding two theme variations in a row result to a  crash.

https://user-images.githubusercontent.com/93253123/217037249-1ce1d56d-beb6-4435-83ad-9f8a07fe0e96.mp4



### Steps to reproduce

1. Create a project.
2. Create a theme.
3. Double click to go in the theme editor.
4. Click on manage items buttons.
5. In the add type field type a name to add a type.
6. type another name to add a second type.
7. Crash.

### Minimal reproduction project

[ThemeVariationCrash.zip](https://github.com/godotengine/godot/files/10665863/ThemeVariationCrash.zip)

return make_help_bit(p_text, true);
}
void EditorProperty::menu_option(int p_option) {
	switch (p_option) {
		case MENU_COPY_VALUE: {
			InspectorDock::get_inspector_singleton()->set_property_clipboard(object->get(property));
		} break;
		case MENU_PASTE_VALUE: {
			emit_changed(property, InspectorDock::get_inspector_singleton()->get_property_clipboard());
		} break;
		case MENU_COPY_PROPERTY_PATH: {
			DisplayServer::get_singleton()->clipboard_set(property_path);
		} break;
		case MENU_PIN_VALUE: {
			emit_signal(SNAME("property_pinned"), property, !pinned);
			queue_redraw();
		} break;
		case MENU_OPEN_DOCUMENTATION: {
			ScriptEditor::get_singleton()->goto_help(doc_path);
			EditorNode::get_singleton()->set_visible_editor(EditorNode::EDITOR_SCRIPT);
		} break;
	}
}
void EditorProperty::_bind_methods() {