### 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)

ERR_MAIN_THREAD_GUARD;
	ERR_FAIL_COND(!is_inside_tree());
	ERR_FAIL_COND(p_event.is_null());
	if (disable_input) {
		return;
	}
	if (Engine::get_singleton()->is_editor_hint() && get_tree()->get_edited_scene_root() && get_tree()->get_edited_scene_root()->is_ancestor_of(this)) {
		return;
	}
	local_input_handled = false;
	Ref<InputEvent> ev;
	if (!p_local_coords) {
		ev = _make_input_local(p_event);
	} else {
		ev = p_event;
	}