### 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)

void _gui_control_grab_focus(Control *p_control);
	void _gui_grab_click_focus(Control *p_control);
	void _post_gui_grab_click_focus();
	void _gui_accept_event();
	bool _gui_drop(Control *p_at_control, Point2 p_at_pos, bool p_just_check);
	friend class AudioListener2D;
	void _audio_listener_2d_set(AudioListener2D *p_listener);
	void _audio_listener_2d_remove(AudioListener2D *p_listener);
	friend class Camera2D;
	void _camera_2d_set(Camera2D *p_camera_2d);
	friend class CanvasLayer;
	void _canvas_layer_add(CanvasLayer *p_canvas_layer);
	void _canvas_layer_remove(CanvasLayer *p_canvas_layer);
	void _drop_mouse_over();
	void _drop_mouse_focus();
	void _drop_physics_mouseover(bool p_paused_only = false);
	void _update_canvas_items(Node *p_node);
	friend class Window;
	void _sub_window_update_order();
	void _sub_window_register(Window *p_window);
	void _sub_window_update(Window *p_window);
	void _sub_window_grab_focus(Window *p_window);
	void _sub_window_remove(Window *p_window);
	int _sub_window_find(Window *p_window) const;
	bool _sub_windows_forward_input(const Ref<InputEvent> &p_event);
	SubWindowResize _sub_window_get_resize_margin(Window *p_subwindow, const Point2 &p_point);
	void _update_mouse_over();
	virtual void _update_mouse_over(Vector2 p_pos);
	virtual void _mouse_leave_viewport();
	virtual bool _can_consume_input_events() const { return true; }