### 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)

Callable callable = windows[E->get()].input_event_callback;
				if (callable.is_valid()) {
					callable.callp((const Variant **)&evp, 1, ret, ce);
				}
			}
			in_dispatch_input_event = false;
			return;
		}
	}
	Ref<InputEventFromWindow> event_from_window = p_event;
	if (event_from_window.is_valid() && event_from_window->get_window_id() != INVALID_WINDOW_ID) {
		
		if (windows.has(event_from_window->get_window_id())) {
			Callable callable = windows[event_from_window->get_window_id()].input_event_callback;
			if (callable.is_valid()) {
				callable.callp((const Variant **)&evp, 1, ret, ce);
			}
		}
	} else {
		
		for (const KeyValue<WindowID, WindowData> &E : windows) {
			const Callable callable = E.value.input_event_callback;
			if (callable.is_valid()) {
				callable.callp((const Variant **)&evp, 1, ret, ce);
			}
		}
	}
	in_dispatch_input_event = false;
}
LRESULT CALLBACK MouseProc(int code, WPARAM wParam, LPARAM lParam) {