### 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 gui_is_dragging() const;
	bool gui_is_drag_successful() const;
	Control *gui_find_control(const Point2 &p_global);
	void set_sdf_oversize(SDFOversize p_sdf_oversize);
	SDFOversize get_sdf_oversize() const;
	void set_sdf_scale(SDFScale p_sdf_scale);
	SDFScale get_sdf_scale() const;
	void set_default_canvas_item_texture_filter(DefaultCanvasItemTextureFilter p_filter);
	DefaultCanvasItemTextureFilter get_default_canvas_item_texture_filter() const;
	void set_default_canvas_item_texture_repeat(DefaultCanvasItemTextureRepeat p_repeat);
	DefaultCanvasItemTextureRepeat get_default_canvas_item_texture_repeat() const;
	
	void set_vrs_mode(VRSMode p_vrs_mode);
	VRSMode get_vrs_mode() const;
	void set_vrs_texture(Ref<Texture2D> p_texture);
	Ref<Texture2D> get_vrs_texture() const;
	virtual DisplayServer::WindowID get_window_id() const = 0;
	void set_embedding_subwindows(bool p_embed);
	bool is_embedding_subwindows() const;
	TypedArray<Window> get_embedded_subwindows() const;
	void subwindow_set_popup_safe_rect(Window *p_window, const Rect2i &p_rect);
	Rect2i subwindow_get_popup_safe_rect(Window *p_window) const;
	Viewport *get_parent_viewport() const;
	Window *get_base_window() const;
	void pass_mouse_focus_to(Viewport *p_viewport, Control *p_control);
	void set_canvas_cull_mask(uint32_t p_layers);
	uint32_t get_canvas_cull_mask() const;
	void set_canvas_cull_mask_bit(uint32_t p_layer, bool p_enable);
	bool get_canvas_cull_mask_bit(uint32_t p_layer) const;
	virtual bool is_size_2d_override_stretch_enabled() const { return true; }