### 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)

ae.move_texture_rect->set_texture(get_theme_icon(SNAME("TripleBar"), SNAME("EditorIcons")));
				}
				Size2 min_size = get_theme_stylebox(SNAME("Focus"), SNAME("EditorStyles"))->get_minimum_size();
				ae.margin->add_theme_constant_override("margin_left", min_size.x / 2);
				ae.margin->add_theme_constant_override("margin_top", min_size.y / 2);
				ae.margin->add_theme_constant_override("margin_right", min_size.x / 2);
				ae.margin->add_theme_constant_override("margin_bottom", min_size.y / 2);
				if (ae.erase) {
					ae.erase->set_icon(get_theme_icon(SNAME("Remove"), SNAME("EditorIcons")));
				}
			}
			add_button->set_icon(get_theme_icon(SNAME("Add"), SNAME("EditorIcons")));
			update_minimum_size();
		} break;
		case NOTIFICATION_DRAG_BEGIN: {
			Dictionary dict = get_viewport()->gui_get_drag_data();
			if (dict.has("type") && dict["type"] == "property_array_element" && String(dict["property_array_prefix"]) == array_element_prefix) {
				dropping = true;
				control_dropping->queue_redraw();
			}
		} break;
		case NOTIFICATION_DRAG_END: {
			if (dropping) {
				dropping = false;
				control_dropping->queue_redraw();
			}
		} break;
	}
}
void EditorInspectorArray::_bind_methods() {