### Godot version

v4.0.stable.official [92bee43ad]

### System information

Linux - v4.0.stable.official [92bee43ad]

### Issue description

It gives you the possibility of removing unexisting key/value pairs from a dictionary.

### Steps to reproduce

![image](https://github.com/godotengine/godot/assets/69520693/35beadbe-bfdd-4176-9b26-222bbf69cafa)
![image](https://github.com/godotengine/godot/assets/69520693/7ed647e0-a2af-4e58-9f00-f77b7bc7bb02)
![image](https://github.com/godotengine/godot/assets/69520693/f08bf824-8408-45eb-bb84-f1dc7e19e392)


### Minimal reproduction project

N/A
Button *button = Object::cast_to<Button>(p_button);
	Rect2 rect = button->get_screen_rect();
	change_type->reset_size();
	change_type->set_position(rect.get_end() - Vector2(change_type->get_contents_minimum_size().x, 0));
	change_type->popup();
	changing_type_index = p_index;
}
void EditorPropertyDictionary::_add_key_value() {
	
	if (object->get_new_item_key().get_type() == Variant::NIL) {
		return;
	}
	Dictionary dict = object->get_dict().duplicate();
	dict[object->get_new_item_key()] = object->get_new_item_value();
	object->set_new_item_key(Variant());
	object->set_new_item_value(Variant());
	emit_changed(get_edited_property(), dict, "", false);
	update_property();
}
void EditorPropertyDictionary::_change_type_menu(int p_index) {