### 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)

GDCLASS(EditorPaginator, HBoxContainer);
	int page = 0;
	int max_page = 0;
	Button *first_page_button = nullptr;
	Button *prev_page_button = nullptr;
	LineEdit *page_line_edit = nullptr;
	Label *page_count_label = nullptr;
	Button *next_page_button = nullptr;
	Button *last_page_button = nullptr;
	void _first_page_button_pressed();
	void _prev_page_button_pressed();
	void _page_line_edit_text_submitted(String p_text);
	void _next_page_button_pressed();
	void _last_page_button_pressed();
protected:
	void _notification(int p_what);
	static void _bind_methods();
public:
	void update(int p_page, int p_max_page);
	EditorPaginator();
};
class EditorInspector : public ScrollContainer {