### 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)

ep->object = object;
				if (properties.size()) {
					if (properties.size() == 1) {
						
						ep->property = properties[0];
						ep->property_path = property_prefix + properties[0];
						ep->property_usage = p.usage;
						
					}
					if (!editors[i].label.is_empty()) {
						ep->set_label(editors[i].label);
					} else {
						
						ep->set_label(property_label_string);
					}
					for (int j = 0; j < properties.size(); j++) {
						String prop = properties[j];
						if (!editor_property_map.has(prop)) {
							editor_property_map[prop] = List<EditorProperty *>();
						}
						editor_property_map[prop].push_back(ep);
					}
				}
				EditorInspectorSection *section = Object::cast_to<EditorInspectorSection>(current_vbox->get_parent());
				if (section) {
					ep->connect("property_can_revert_changed", callable_mp(section, &EditorInspectorSection::property_can_revert_changed));
				}
				ep->set_draw_warning(draw_warning);
				ep->set_use_folding(use_folding);