### Godot version

0810ecaafdbee3ea747219e6ab3a8de5d2216a09

### System information

Windows 11, Nvidia 3000, firefox

### Issue description

Exporting the gltf file is corrupt in blender.

### Steps to reproduce

1. Open project.
2. Export as glb
3. Open in blender
4. Blender display many warnings

![image](https://user-images.githubusercontent.com/32321/216740742-de662c5c-f5c3-44b5-a36e-8ad33defdbba.png)


### Minimal reproduction project

https://cdn.discordapp.com/attachments/598003845657788438/1071249610896580691/Test_Game_Project.zip


MultiMeshInstance3D *p_multi_mesh_instance,
		GLTFNodeIndex p_parent_node_index,
		GLTFNodeIndex p_root_node_index,
		Ref<GLTFNode> p_gltf_node, Ref<GLTFState> p_state) {
	ERR_FAIL_COND(!p_multi_mesh_instance);
	Ref<MultiMesh> multi_mesh = p_multi_mesh_instance->get_multimesh();
	if (multi_mesh.is_null()) {
		return;
	}
	Ref<GLTFMesh> gltf_mesh;
	gltf_mesh.instantiate();
	Ref<Mesh> mesh = multi_mesh->get_mesh();
	if (mesh.is_null()) {
		return;
	}
	gltf_mesh->set_name(multi_mesh->get_name());
	Ref<ImporterMesh> importer_mesh;
	importer_mesh.instantiate();
	Ref<ArrayMesh> array_mesh = multi_mesh->get_mesh();
	if (array_mesh.is_valid()) {
		importer_mesh->set_blend_shape_mode(array_mesh->get_blend_shape_mode());
		for (int32_t blend_i = 0; blend_i < array_mesh->get_blend_shape_count(); blend_i++) {
			importer_mesh->add_blend_shape(array_mesh->get_blend_shape_name(blend_i));
		}
	}
	for (int32_t surface_i = 0; surface_i < mesh->get_surface_count(); surface_i++) {
		Ref<Material> mat = mesh->surface_get_material(surface_i);
		String material_name;
		if (mat.is_valid()) {