### 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)
diff.x = MIN(diff.x, limit.x);
						diff.y = 0;
						r.position += diff;
						r.size -= diff;
					} break;
					case SUB_WINDOW_RESIZE_RIGHT: {
						diff.x = MAX(diff.x, -limit.x);
						r.size.x += diff.x;
					} break;
					case SUB_WINDOW_RESIZE_BOTTOM_LEFT: {
						diff.x = MIN(diff.x, limit.x);
						diff.y = MAX(diff.y, -limit.y);
						r.position.x += diff.x;
						r.size.x -= diff.x;
						r.size.y += diff.y;
					} break;
					case SUB_WINDOW_RESIZE_BOTTOM: {
						diff.y = MAX(diff.y, -limit.y);
						r.size.y += diff.y;
					} break;
					case SUB_WINDOW_RESIZE_BOTTOM_RIGHT: {
						diff.x = MAX(diff.x, -limit.x);
						diff.y = MAX(diff.y, -limit.y);
						r.size += diff;
					} break;
					default: {
					}
				}
				Size2i max_size = gui.subwindow_focused->get_max_size();
				if ((max_size.x > 0 || max_size.y > 0) && (max_size.x >= min_size.x && max_size.y >= min_size.y)) {