### 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)

deletable = p_deletable;
	queue_redraw();
	queue_sort();
}
bool EditorProperty::is_deletable() const {
	return deletable;
}
bool EditorProperty::is_keying() const {
	return keying;
}
bool EditorProperty::is_draw_warning() const {
	return draw_warning;
}
void EditorProperty::_focusable_focused(int p_index) {
	if (!selectable) {
		return;
	}
	bool already_selected = selected;
	selected = true;
	selected_focusable = p_index;
	queue_redraw();
	if (!already_selected && selected) {
		emit_signal(SNAME("selected"), property, selected_focusable);
	}
}
void EditorProperty::add_focusable(Control *p_control) {