### 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)

if (updating_tree) {
		return;
	}
	TreeItem *edited_item = import_items_tree->get_edited();
	if (!edited_item) {
		return;
	}
	updating_tree = true;
	int edited_column = import_items_tree->get_edited_column();
	bool is_checked = edited_item->is_checked(edited_column);
	if (is_checked) {
		if (edited_column == IMPORT_ITEM_DATA) {
			edited_item->set_checked(IMPORT_ITEM, true);
			edited_item->propagate_check(IMPORT_ITEM);
		}
	} else {
		if (edited_column == IMPORT_ITEM) {
			edited_item->set_checked(IMPORT_ITEM_DATA, false);
			edited_item->propagate_check(IMPORT_ITEM_DATA);
		}
	}
	edited_item->propagate_check(edited_column);
	updating_tree = false;
}
void ThemeItemImportTree::_check_propagated_to_tree_item(Object *p_obj, int p_column) {