### 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)

EditorInspectorSection();
	~EditorInspectorSection();
};
class EditorInspectorArray : public EditorInspectorSection {
	GDCLASS(EditorInspectorArray, EditorInspectorSection);
	enum Mode {
		MODE_NONE,
		MODE_USE_COUNT_PROPERTY,
		MODE_USE_MOVE_ARRAY_ELEMENT_FUNCTION,
	} mode;
	StringName count_property;
	StringName array_element_prefix;
	String swap_method;
	int count = 0;
	VBoxContainer *elements_vbox = nullptr;
	Control *control_dropping = nullptr;
	bool dropping = false;
	Button *add_button = nullptr;
	AcceptDialog *resize_dialog = nullptr;
	SpinBox *new_size_spin_box = nullptr;
	
	int page_length = 5;
	int page = 0;
	int max_page = 0;
	int begin_array_index = 0;
	int end_array_index = 0;
	bool read_only = false;
	bool movable = true;
	bool numbered = false;
	enum MenuOptions {