### 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)
Vector2 subwindow_drag_from;
		Vector2 subwindow_drag_pos;
		Rect2i subwindow_drag_close_rect;
		bool subwindow_drag_close_inside = false;
		SubWindowResize subwindow_resize_mode;
		Rect2i subwindow_resize_from_rect;
		Vector<SubWindow> sub_windows; 
	} gui;
	DefaultCanvasItemTextureFilter default_canvas_item_texture_filter = DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_LINEAR;
	DefaultCanvasItemTextureRepeat default_canvas_item_texture_repeat = DEFAULT_CANVAS_ITEM_TEXTURE_REPEAT_DISABLED;
	bool disable_input = false;
	bool _gui_call_input(Control *p_control, const Ref<InputEvent> &p_input);
	void _gui_call_notification(Control *p_control, int p_what);
	void _gui_sort_roots();
	Control *_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_global, const Transform2D &p_xform);
	void _gui_input_event(Ref<InputEvent> p_event);
	void _perform_drop(Control *p_control = nullptr, Point2 p_pos = Point2());
	void _gui_cleanup_internal_state(Ref<InputEvent> p_event);
	Ref<InputEvent> _make_input_local(const Ref<InputEvent> &ev);
	friend class Control;
	List<Control *>::Element *_gui_add_root_control(Control *p_control);
	void _gui_remove_root_control(List<Control *>::Element *RI);
	String _gui_get_tooltip(Control *p_control, const Vector2 &p_pos, Control **r_tooltip_owner = nullptr);
	void _gui_cancel_tooltip();
	void _gui_show_tooltip();
	void _gui_remove_control(Control *p_control);
	void _gui_hide_control(Control *p_control);
	void _gui_force_drag(Control *p_base, const Variant &p_data, Control *p_control);
	void _gui_set_drag_preview(Control *p_base, Control *p_control);
	Control *_gui_get_drag_preview();