### 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)

RBMap<int, Vector2>::Element *curr = touch_state.find(idx);
	if (!curr) {
		return;
	}
	if (curr->get() == Vector2(p_x, p_y)) {
		return;
	}
	Ref<InputEventScreenDrag> event;
	event.instantiate();
	event->set_window_id(p_window);
	event->set_index(idx);
	event->set_position(Vector2(p_x, p_y));
	event->set_relative(Vector2(p_x, p_y) - curr->get());
	Input::get_singleton()->parse_input_event(event);
	curr->get() = Vector2(p_x, p_y);
}
void DisplayServerWindows::_send_window_event(const WindowData &wd, WindowEvent p_event) {