### 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)
RenderingServer::get_singleton()->canvas_item_clear(contact_2d_debug);
				RenderingServer::get_singleton()->canvas_item_set_draw_index(contact_2d_debug, 0xFFFFF); 
				Vector<Vector2> points = PhysicsServer2D::get_singleton()->space_get_contacts(find_world_2d()->get_space());
				int point_count = PhysicsServer2D::get_singleton()->space_get_contact_count(find_world_2d()->get_space());
				Color ccol = get_tree()->get_debug_collision_contact_color();
				for (int i = 0; i < point_count; i++) {
					RenderingServer::get_singleton()->canvas_item_add_rect(contact_2d_debug, Rect2(points[i] - Vector2(2, 2), Vector2(5, 5)), ccol);
				}
			}
#ifndef _3D_DISABLED
			if (get_tree()->is_debugging_collisions_hint() && contact_3d_debug_multimesh.is_valid()) {
				Vector<Vector3> points = PhysicsServer3D::get_singleton()->space_get_contacts(find_world_3d()->get_space());
				int point_count = PhysicsServer3D::get_singleton()->space_get_contact_count(find_world_3d()->get_space());
				RS::get_singleton()->multimesh_set_visible_instances(contact_3d_debug_multimesh, point_count);
				for (int i = 0; i < point_count; i++) {
					Transform3D point_transform;
					point_transform.origin = points[i];
					RS::get_singleton()->multimesh_instance_set_transform(contact_3d_debug_multimesh, i, point_transform);
				}
			}
#endif 
		} break;
		case NOTIFICATION_VP_MOUSE_ENTER: {
			gui.mouse_in_viewport = true;
		} break;
		case NOTIFICATION_VP_MOUSE_EXIT: {
			gui.mouse_in_viewport = false;
			_drop_physics_mouseover();
			_drop_mouse_over();