### 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)

if (dropping || dropping_for_unfold) {
				dropping_unfold_timer->stop();
			}
			queue_redraw();
		} break;
	}
}
Size2 EditorInspectorSection::get_minimum_size() const {
	Size2 ms;
	for (int i = 0; i < get_child_count(); i++) {
		Control *c = Object::cast_to<Control>(get_child(i));
		if (!c) {
			continue;
		}
		if (c->is_set_as_top_level()) {
			continue;
		}
		if (!c->is_visible()) {
			continue;
		}
		Size2 minsize = c->get_combined_minimum_size();
		ms.width = MAX(ms.width, minsize.width);
		ms.height = MAX(ms.height, minsize.height);
	}
	Ref<Font> font = get_theme_font(SNAME("font"), SNAME("Tree"));
	int font_size = get_theme_font_size(SNAME("font_size"), SNAME("Tree"));
	ms.height += font->get_height(font_size) + get_theme_constant(SNAME("v_separation"), SNAME("Tree"));
	ms.width += get_theme_constant(SNAME("inspector_margin"), SNAME("Editor"));
	int section_indent_size = get_theme_constant(SNAME("indent_size"), SNAME("EditorInspectorSection"));
	if (indent_depth > 0 && section_indent_size > 0) {