### 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)

bool _camera_3d_add(Camera3D *p_camera); 
	void _camera_3d_remove(Camera3D *p_camera);
	void _camera_3d_make_next_current(Camera3D *p_exclude);
	void enable_camera_3d_override(bool p_enable);
	bool is_camera_3d_override_enabled() const;
	void set_camera_3d_override_transform(const Transform3D &p_transform);
	Transform3D get_camera_3d_override_transform() const;
	void set_camera_3d_override_perspective(real_t p_fovy_degrees, real_t p_z_near, real_t p_z_far);
	void set_camera_3d_override_orthogonal(real_t p_size, real_t p_z_near, real_t p_z_far);
	void set_disable_3d(bool p_disable);
	bool is_3d_disabled() const;
	Ref<World3D> world_3d;
	Ref<World3D> own_world_3d;
	void set_world_3d(const Ref<World3D> &p_world_3d);
	Ref<World3D> get_world_3d() const;
	Ref<World3D> find_world_3d() const;
	void _own_world_3d_changed();
	void set_use_own_world_3d(bool p_use_own_world_3d);
	bool is_using_own_world_3d() const;
	void _propagate_enter_world_3d(Node *p_node);
	void _propagate_exit_world_3d(Node *p_node);
	void set_use_xr(bool p_use_xr);
	bool is_using_xr();
#endif 
	void _propagate_world_2d_changed(Node *p_node);
	void _validate_property(PropertyInfo &p_property) const;
	Viewport();
	~Viewport();
};
class SubViewport : public Viewport {