### 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)

#include "viewport.h"
#include "core/config/project_settings.h"
#include "core/debugger/engine_debugger.h"
#include "core/object/message_queue.h"
#include "core/string/translation.h"
#include "core/templates/pair.h"
#include "core/templates/sort_array.h"
#include "scene/2d/audio_listener_2d.h"
#include "scene/2d/camera_2d.h"
#include "scene/2d/collision_object_2d.h"
#ifndef _3D_DISABLED
#include "scene/3d/audio_listener_3d.h"
#include "scene/3d/camera_3d.h"
#include "scene/3d/collision_object_3d.h"
#include "scene/3d/world_environment.h"
#endif 
#include "scene/gui/control.h"
#include "scene/gui/label.h"
#include "scene/gui/popup.h"
#include "scene/gui/popup_menu.h"
#include "scene/gui/subviewport_container.h"
#include "scene/main/canvas_layer.h"
#include "scene/main/window.h"