### Godot version

v4.0 rc6

### System information

Windows 10

### Issue description

When using a ViewportTexture from a SubViewport on a TextureRect, it throws errors after running the scene once and then switching scenes in the editor.
![Pasted image 20230227212626](https://user-images.githubusercontent.com/44676282/221680047-984fa03e-33d1-4856-9a7f-1700b28423cf.png)


### Steps to reproduce

Run the canvas-scene once.
Switch to another scene in the editor.
Switch back to the canvas-scene

### Minimal reproduction project

[ViewportTextureError.zip](https://github.com/godotengine/godot/files/10844099/ViewportTextureError.zip)

#ifndef _3D_DISABLED
				PhysicsServer3D::get_singleton()->space_set_debug_contacts(find_world_3d()->get_space(), get_tree()->get_collision_debug_contact_count());
				contact_3d_debug_multimesh = RenderingServer::get_singleton()->multimesh_create();
				RenderingServer::get_singleton()->multimesh_allocate_data(contact_3d_debug_multimesh, get_tree()->get_collision_debug_contact_count(), RS::MULTIMESH_TRANSFORM_3D, false);
				RenderingServer::get_singleton()->multimesh_set_visible_instances(contact_3d_debug_multimesh, 0);
				RenderingServer::get_singleton()->multimesh_set_mesh(contact_3d_debug_multimesh, get_tree()->get_debug_contact_mesh()->get_rid());
				contact_3d_debug_instance = RenderingServer::get_singleton()->instance_create();
				RenderingServer::get_singleton()->instance_set_base(contact_3d_debug_instance, contact_3d_debug_multimesh);
				RenderingServer::get_singleton()->instance_set_scenario(contact_3d_debug_instance, find_world_3d()->get_scenario());
				RenderingServer::get_singleton()->instance_geometry_set_flag(contact_3d_debug_instance, RS::INSTANCE_FLAG_DRAW_NEXT_FRAME_IF_VISIBLE, true);
#endif 
				set_physics_process_internal(true);
			}
		} break;
		case NOTIFICATION_READY: {
#ifndef _3D_DISABLED
			if (audio_listener_3d_set.size() && !audio_listener_3d) {
				AudioListener3D *first = nullptr;
				for (AudioListener3D *E : audio_listener_3d_set) {
					if (first == nullptr || first->is_greater_than(E)) {
						first = E;
					}
				}
				if (first) {
					first->make_current();
				}
			}
			if (camera_3d_set.size() && !camera_3d) {
				
				Camera3D *first = nullptr;