### Godot version

v4.0.beta17.mono.official [c40020513]

### System information

Windows 11 22H2

### Issue description

If a focused subwindow is destroyed, DisplayServerWindows may still attempt to send mouse motion events to that window, because `last_focused_window` isn't updated until another window is focused.

```
ERROR: Condition "!windows.has(p_window)" is true. Returning: Point2i()
   at: window_get_position (platform/windows/display_server_windows.cpp:999)
```

### Steps to reproduce

Run the MRP, click some non-Godot application window to focus it, then click the "CLOSE" button in the secondary window. This destroys the window without re-focusing the main window, so hovering the mouse over the main window will produce the error message above.

### Minimal reproduction project

[native_windows_hover.zip](https://github.com/godotengine/godot/files/10573386/native_windows_hover.zip)

}
			if (uMsg != WM_MOUSEWHEEL && uMsg != WM_MOUSEHWHEEL) {
				if (mb->is_pressed()) {
					if (++pressrc > 0 && mouse_mode != MOUSE_MODE_CAPTURED) {
						SetCapture(hWnd);
					}
				} else {
					if (--pressrc <= 0) {
						if (mouse_mode != MOUSE_MODE_CAPTURED) {
							ReleaseCapture();
						}
						pressrc = 0;
					}
				}
			} else {
				
				POINT coords;
				coords.x = mb->get_position().x;
				coords.y = mb->get_position().y;
				ScreenToClient(hWnd, &coords);
				mb->set_position(Vector2(coords.x, coords.y));
			}
			mb->set_global_position(mb->get_position());
			Input::get_singleton()->parse_input_event(mb);
			if (mb->is_pressed() && mb->get_button_index() >= MouseButton::WHEEL_UP && mb->get_button_index() <= MouseButton::WHEEL_RIGHT) {
				
				Ref<InputEventMouseButton> mbd = mb->duplicate();
				mbd->set_window_id(window_id);
				last_button_state.clear_flag(mouse_button_to_mask(mbd->get_button_index()));
				mbd->set_button_mask(last_button_state);