### 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)
Control *c = over;
				Vector2 cpos = pos;
				while (c) {
					if (!gui.mouse_focus_mask.is_empty() || c->has_point(cpos)) {
						cursor_shape = c->get_cursor_shape(cpos);
					} else {
						cursor_shape = Control::CURSOR_ARROW;
					}
					cpos = c->get_transform().xform(cpos);
					if (cursor_shape != Control::CURSOR_ARROW) {
						break;
					}
					if (c->data.mouse_filter == Control::MOUSE_FILTER_STOP) {
						break;
					}
					if (c->is_set_as_top_level()) {
						break;
					}
					c = c->get_parent_control();
				}
			}
			ds_cursor_shape = (DisplayServer::CursorShape)cursor_shape;
			bool stopped = false;
			if (over && over->can_process()) {
				stopped = _gui_call_input(over, mm);
			}
			if (stopped) {
				set_input_as_handled();
			}
		}