### 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)
if (viewport_under) {
				if (viewport_under != this) {
					Transform2D ai = viewport_under->get_final_transform().affine_inverse();
					viewport_pos = ai.xform(viewport_pos);
				}
				
				gui.drag_mouse_over = viewport_under->gui_find_control(viewport_pos);
				if (gui.drag_mouse_over) {
					Transform2D localizer = gui.drag_mouse_over->get_global_transform_with_canvas().affine_inverse();
					gui.drag_mouse_over_pos = localizer.xform(viewport_pos);
					bool can_drop = _gui_drop(gui.drag_mouse_over, gui.drag_mouse_over_pos, true);
					if (!can_drop) {
						ds_cursor_shape = DisplayServer::CURSOR_FORBIDDEN;
					} else {
						ds_cursor_shape = DisplayServer::CURSOR_CAN_DROP;
					}
				}
			} else {
				gui.drag_mouse_over = nullptr;
			}
		}
		if (DisplayServer::get_singleton()->has_feature(DisplayServer::FEATURE_CURSOR_SHAPE)) {
			DisplayServer::get_singleton()->cursor_set_shape(ds_cursor_shape);
		}
	}
	Ref<InputEventScreenTouch> touch_event = p_event;
	if (touch_event.is_valid()) {
		Size2 pos = touch_event->get_position();
		const int touch_index = touch_event->get_index();
		if (touch_event->is_pressed()) {