### 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)

Control *mouse_over = nullptr;
		Window *subwindow_over = nullptr; 
		Window *windowmanager_window_over = nullptr; 
		Control *drag_mouse_over = nullptr;
		Vector2 drag_mouse_over_pos;
		Control *tooltip_control = nullptr;
		Window *tooltip_popup = nullptr;
		Label *tooltip_label = nullptr;
		Point2 tooltip_pos;
		Point2 last_mouse_pos;
		Point2 drag_accum;
		bool drag_attempted = false;
		Variant drag_data;
		ObjectID drag_preview_id;
		Ref<SceneTreeTimer> tooltip_timer;
		double tooltip_delay = 0.0;
		bool roots_order_dirty = false;
		List<Control *> roots;
		HashSet<ObjectID> canvas_parents_with_dirty_order;
		int canvas_sort_index = 0; 
		bool dragging = false;
		bool drag_successful = false;
		bool embed_subwindows_hint = false;
		Window *subwindow_focused = nullptr;
		Window *currently_dragged_subwindow = nullptr;
		SubWindowDrag subwindow_drag = SUB_WINDOW_DRAG_DISABLED;
		Vector2 subwindow_drag_from;
		Vector2 subwindow_drag_pos;
		Rect2i subwindow_drag_close_rect;
		bool subwindow_drag_close_inside = false;