### 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)

_THREAD_SAFE_METHOD_
	MSG msg;
	if (!drop_events) {
		joypad->process_joypads();
	}
	while (PeekMessageW(&msg, nullptr, 0, 0, PM_REMOVE)) {
		TranslateMessage(&msg);
		DispatchMessageW(&msg);
	}
	if (!drop_events) {
		_process_key_events();
		Input::get_singleton()->flush_buffered_events();
	}
}
void DisplayServerWindows::force_process_and_drop_events() {