### 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


bool retflag = true;
	_check_visibility(p_current, retflag);
	if (retflag) {
		return;
	}
	Ref<GLTFNode> gltf_node;
	gltf_node.instantiate();
	gltf_node->set_name(_gen_unique_name(p_state, p_current->get_name()));
	if (cast_to<Node3D>(p_current)) {
		Node3D *spatial = cast_to<Node3D>(p_current);
		_convert_spatial(p_state, spatial, gltf_node);
	}
	if (cast_to<MeshInstance3D>(p_current)) {
		MeshInstance3D *mi = cast_to<MeshInstance3D>(p_current);
		_convert_mesh_instance_to_gltf(mi, p_state, gltf_node);
	} else if (cast_to<BoneAttachment3D>(p_current)) {
		BoneAttachment3D *bone = cast_to<BoneAttachment3D>(p_current);
		_convert_bone_attachment_to_gltf(bone, p_state, p_gltf_parent, p_gltf_root, gltf_node);
		return;
	} else if (cast_to<Skeleton3D>(p_current)) {
		Skeleton3D *skel = cast_to<Skeleton3D>(p_current);
		_convert_skeleton_to_gltf(skel, p_state, p_gltf_parent, p_gltf_root, gltf_node);
		
		return;
	} else if (cast_to<MultiMeshInstance3D>(p_current)) {
		MultiMeshInstance3D *multi = cast_to<MultiMeshInstance3D>(p_current);
		_convert_multi_mesh_instance_to_gltf(multi, p_gltf_parent, p_gltf_root, gltf_node, p_state);
#ifdef MODULE_CSG_ENABLED
	} else if (cast_to<CSGShape3D>(p_current)) {
		CSGShape3D *shape = cast_to<CSGShape3D>(p_current);