### 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


if (BaseMaterial3D::TextureChannel::TEXTURE_CHANNEL_RED == metalness_channel) {
							c.b = metallness_image->get_pixel(w, h).r;
						} else if (BaseMaterial3D::TextureChannel::TEXTURE_CHANNEL_GREEN == metalness_channel) {
							c.b = metallness_image->get_pixel(w, h).g;
						} else if (BaseMaterial3D::TextureChannel::TEXTURE_CHANNEL_BLUE == metalness_channel) {
							c.b = metallness_image->get_pixel(w, h).b;
						} else if (BaseMaterial3D::TextureChannel::TEXTURE_CHANNEL_ALPHA == metalness_channel) {
							c.b = metallness_image->get_pixel(w, h).a;
						}
					}
					orm_image->set_pixel(w, h, c);
				}
			}
			orm_image->generate_mipmaps();
			orm_texture->set_image(orm_image);
			GLTFTextureIndex orm_texture_index = -1;
			if (has_ao || has_roughness || has_metalness) {
				orm_texture->set_name(material->get_name() + "_orm");
				orm_texture_index = _set_texture(p_state, orm_texture, base_material->get_texture_filter(), base_material->get_flag(BaseMaterial3D::FLAG_USE_TEXTURE_REPEAT));
			}
			if (has_ao) {
				Dictionary occt;
				occt["index"] = orm_texture_index;
				d["occlusionTexture"] = occt;
			}
			if (has_roughness || has_metalness) {
				mrt["index"] = orm_texture_index;
				Dictionary extensions = _serialize_texture_transform_uv1(material);
				if (!extensions.is_empty()) {
					mrt["extensions"] = extensions;