### 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)

String action_name;
	if (p_element_index < 0) {
		action_name = vformat("Add element to property array with prefix %s.", array_element_prefix);
	} else if (p_to_pos < 0) {
		action_name = vformat("Remove element %d from property array with prefix %s.", p_element_index, array_element_prefix);
	} else {
		action_name = vformat("Move element %d to position %d in property array with prefix %s.", p_element_index, p_to_pos, array_element_prefix);
	}
	EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
	undo_redo->create_action(action_name);
	if (mode == MODE_USE_MOVE_ARRAY_ELEMENT_FUNCTION) {
		
		Callable move_function = EditorNode::get_singleton()->get_editor_data().get_move_array_element_function(object->get_class_name());
		if (move_function.is_valid()) {
			Variant args[] = { undo_redo, object, array_element_prefix, p_element_index, p_to_pos };