### Godot version

4.0 Beta10

### System information

Ubuntu 22.04 (Tuxedo OS)

### Issue description

After importing an *.obj file as a scene, if you click on the mesh in the import settings Godot crashes.

![Screenshot from 2022-12-24 14-38-23](https://user-images.githubusercontent.com/25522325/209452619-3c0ed61b-deaa-4fb6-8ff5-5aa11ff4ed33.png)

I the above screenshot, clicking in the circled area will crash Godot.

### Steps to reproduce

Import .obj file into a project.
Select the file.
Go to import setting.
Change OBJ As Mesh to Scene.
Click Reimport.
Click Save Scenes, Re-Import, and Restart.
Once restarted, open the advanced import settings on the object.
Click the are circled in the description, or in the meshes tab.

### Minimal reproduction project

N/A

Specifically, I lack the distribution rights of the .obj files I am using.  Any .obj file should do, this happened to me on at least 4 different .obj files.
if (l.begins_with("o ")) {
				name = l.substr(2, l.length()).strip_edges();
			}
			if (l.begins_with("usemtl ")) {
				current_material = l.replace("usemtl", "").strip_edges();
			}
			if (l.begins_with("g ")) {
				current_group = l.substr(2, l.length()).strip_edges();
			}
		} else if (l.begins_with("mtllib ")) { 
			current_material_library = l.replace("mtllib", "").strip_edges();
			if (!material_map.has(current_material_library)) {
				HashMap<String, Ref<StandardMaterial3D>> lib;
				String lib_path = current_material_library;
				if (lib_path.is_relative_path()) {
					lib_path = p_path.get_base_dir().path_join(current_material_library);
				}
				Error err = _parse_material_library(lib_path, lib, r_missing_deps);
				if (err == OK) {
					material_map[current_material_library] = lib;
				}
			}
		}
	}
	if (p_single_mesh) {
		r_meshes.push_back(mesh);
	}
	return OK;
}
Node *EditorOBJImporter::import_scene(const String &p_path, uint32_t p_flags, const HashMap<StringName, Variant> &p_options, List<String> *r_missing_deps, Error *r_err) {