### 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.
Ref<FileAccess> f = FileAccess::open(p_path, FileAccess::READ);
	ERR_FAIL_COND_V_MSG(f.is_null(), ERR_CANT_OPEN, vformat("Couldn't open OBJ file '%s', it may not exist or not be readable.", p_path));
	Ref<ArrayMesh> mesh;
	mesh.instantiate();
	bool generate_tangents = p_generate_tangents;
	Vector3 scale_mesh = p_scale_mesh;
	Vector3 offset_mesh = p_offset_mesh;
	int mesh_flags = 0;
	Vector<Vector3> vertices;
	Vector<Vector3> normals;
	Vector<Vector2> uvs;
	Vector<Color> colors;
	String name;
	HashMap<String, HashMap<String, Ref<StandardMaterial3D>>> material_map;
	Ref<SurfaceTool> surf_tool = memnew(SurfaceTool);
	surf_tool->begin(Mesh::PRIMITIVE_TRIANGLES);
	String current_material_library;
	String current_material;
	String current_group;
	uint32_t smooth_group = 0;
	bool smoothing = true;
	while (true) {
		String l = f->get_line().strip_edges();
		while (l.length() && l[l.length() - 1] == '\\') {