### 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)
title_bar.size.y = title_height;
				if (title_bar.has_point(mb->get_position())) {
					click_on_window = true;
					int close_h_ofs = sw.window->get_theme_constant(SNAME("close_h_offset"));
					int close_v_ofs = sw.window->get_theme_constant(SNAME("close_v_offset"));
					Ref<Texture2D> close_icon = sw.window->get_theme_icon(SNAME("close"));
					Rect2 close_rect;
					close_rect.position = Vector2(r.position.x + r.size.x - close_h_ofs, r.position.y - close_v_ofs);
					close_rect.size = close_icon->get_size();
					if (gui.subwindow_focused != sw.window) {
						
						_sub_window_grab_focus(sw.window);
					}
					if (close_rect.has_point(mb->get_position())) {
						gui.subwindow_drag = SUB_WINDOW_DRAG_CLOSE;
						gui.subwindow_drag_close_inside = true; 
						gui.subwindow_drag_close_rect = close_rect;
					} else {
						gui.subwindow_drag = SUB_WINDOW_DRAG_MOVE;
					}
					gui.subwindow_drag_from = mb->get_position();
					gui.subwindow_drag_pos = sw.window->get_position();
					_sub_window_update(sw.window);
				} else {
					gui.subwindow_resize_mode = _sub_window_get_resize_margin(sw.window, mb->get_position());
					if (gui.subwindow_resize_mode != SUB_WINDOW_RESIZE_DISABLED) {
						if (gui.subwindow_focused != sw.window) {
							
							_sub_window_grab_focus(sw.window);
						}