### 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)

if (ABS(dist_y) > limit) {
		return SUB_WINDOW_RESIZE_DISABLED;
	}
	if (dist_x < 0 && dist_y < 0) {
		return SUB_WINDOW_RESIZE_TOP_LEFT;
	}
	if (dist_x == 0 && dist_y < 0) {
		return SUB_WINDOW_RESIZE_TOP;
	}
	if (dist_x > 0 && dist_y < 0) {
		return SUB_WINDOW_RESIZE_TOP_RIGHT;
	}
	if (dist_x < 0 && dist_y == 0) {
		return SUB_WINDOW_RESIZE_LEFT;
	}
	if (dist_x > 0 && dist_y == 0) {
		return SUB_WINDOW_RESIZE_RIGHT;
	}
	if (dist_x < 0 && dist_y > 0) {
		return SUB_WINDOW_RESIZE_BOTTOM_LEFT;
	}
	if (dist_x == 0 && dist_y > 0) {
		return SUB_WINDOW_RESIZE_BOTTOM;
	}
	if (dist_x > 0 && dist_y > 0) {
		return SUB_WINDOW_RESIZE_BOTTOM_RIGHT;
	}
	return SUB_WINDOW_RESIZE_DISABLED;
}
bool Viewport::_sub_windows_forward_input(const Ref<InputEvent> &p_event) {