### 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)
// Erase itself from viewport textures.
	for (ViewportTexture *E : viewport_textures) {
		E->vp = nullptr;
	}
	ERR_FAIL_NULL(RenderingServer::get_singleton());
	RenderingServer::get_singleton()->free(viewport);
}
//
void SubViewport::set_size(const Size2i &p_size) {
	_internal_set_size(p_size);
}
void SubViewport::set_size_force(const Size2i &p_size) {
	// Use only for setting the size from the parent SubViewportContainer with enabled stretch mode.
	// Don't expose function to scripting.
	_internal_set_size(p_size, true);
}
void SubViewport::_internal_set_size(const Size2i &p_size, bool p_force) {
	SubViewportContainer *c = Object::cast_to<SubViewportContainer>(get_parent());
	if (!p_force && c && c->is_stretch_enabled()) {
#ifdef DEBUG_ENABLED
		WARN_PRINT("Can't change the size of a `SubViewport` with a `SubViewportContainer` parent that has `stretch` enabled. Set `SubViewportContainer.stretch` to `false` to allow changing the size manually.");
#endif // DEBUG_ENABLED
		return;
	}
	_set_size(p_size, _get_size_2d_override(), true);
	if (c) {
		c->update_minimum_size();
	}
}
Size2i SubViewport::get_size() const {