### Godot version

v4.0.beta17.official [c40020513]

### System information

macOS 13.0.1

### Issue description

When a `Control` node is over a `SubViewportContainer` (with a `SubViewport` as a child), both in Full Rect anchors, asking for the get_viewport().get_mouse_position() from a scene inside the `SubViewport` returns (0, 0) as the position of the mouse.

This wasn't happening in at least Beta 15. I was getting the mouse position without any problems before Beta 17. I didn't try Beta 16.

### Steps to reproduce

1. Create a `Control` node
2. Add two children: A `SubViewportContainer` and a `Control` node
3. Put both in Full Rect anchors so the `Control` node (child) is covering the `SubViewportContainer`
4. Ask for the get_viewport().get_mouse_position() from inside a scene of the `SubViewport`

As you can see in this screenshot: asking for the mouse position from inside the `Node2D` script always returns (0, 0).

<img width="1533" alt="SubViewportContainerIssue" src="https://user-images.githubusercontent.com/91340577/217051768-d9c2e8ad-40ca-4c6d-bb98-f6a7c9c6081f.png">

Only If the `Control` (child) mouse filtering is set to _Ignore_ you can get the mouse position. But with that you are losing the mouse inputs from that `Control` node.

You can find the setup of these nodes in the MRP.


### Minimal reproduction project

Run the main scene (control.tscn) and move the mouse around the screen. Look for the print in the Output tab.

[SubViewportMousePositionIssue.zip](https://github.com/godotengine/godot/files/10667894/SubViewportMousePositionIssue.zip)
void _gui_remove_focus_for_window(Node *p_window);
	void _gui_unfocus_control(Control *p_control);
	bool _gui_control_has_focus(const Control *p_control);
	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);
	bool _sub_windows_forward_input(const Ref<InputEvent> &p_event);
	SubWindowResize _sub_window_get_resize_margin(Window *p_subwindow, const Point2 &p_point);
	virtual bool _can_consume_input_events() const { return true; }