### 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 RESOURCE_H
#define RESOURCE_H
#include "core/io/resource_uid.h"
#include "core/object/class_db.h"
#include "core/object/ref_counted.h"
#include "core/templates/safe_refcount.h"
#include "core/templates/self_list.h"
class Node;
#define RES_BASE_EXTENSION(m_ext)                                                                                   \
public:                                                                                                             \
	static void register_custom_data_to_otdb() { ClassDB::add_resource_base_extension(m_ext, get_class_static()); } \
	virtual String get_base_extension() const override { return m_ext; }                                            \
                                                                                                                    \
private:
class Resource : public RefCounted {
	GDCLASS(Resource, RefCounted);
public:
	static void register_custom_data_to_otdb() { ClassDB::add_resource_base_extension("res", get_class_static()); }
	virtual String get_base_extension() const { return "res"; }
private:
	friend class ResBase;
	friend class ResourceCache;
	String name;
	String path_cache;
	String scene_unique_id;