### 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)

can_pin = false;
	pin_hidden = true;
	if (read_only) {
		return;
	}
	if (Node *node = Object::cast_to<Node>(object)) {
		
		if (!node->get_owner()) {
			bool is_scene_root = false;
			for (int i = 0; i < EditorNode::get_singleton()->get_editor_data().get_edited_scene_count(); ++i) {
				if (EditorNode::get_singleton()->get_editor_data().get_edited_scene_root(i) == node) {
					is_scene_root = true;
					break;
				}
			}
			if (!is_scene_root) {
				return;
			}
		}
		if (!_is_value_potential_override(node, property)) {
			return;
		}
		pin_hidden = false;
		{
			HashSet<StringName> storable_properties;
			node->get_storable_properties(storable_properties);
			if (storable_properties.has(node->get_property_store_alias(property))) {
				can_pin = true;
			}