### 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)

_update_window_style(p_window, false);
	} else {
		wd.multiwindow_fs = true;
		_update_window_style(p_window, false);
	}
	if ((p_mode == WINDOW_MODE_FULLSCREEN || p_mode == WINDOW_MODE_EXCLUSIVE_FULLSCREEN) && !wd.fullscreen) {
		if (wd.minimized) {
			ShowWindow(wd.hWnd, SW_RESTORE);
		}
		wd.was_maximized = wd.maximized;
		if (wd.pre_fs_valid) {
			GetWindowRect(wd.hWnd, &wd.pre_fs_rect);
		}
		int cs = window_get_current_screen(p_window);
		Point2 pos = screen_get_position(cs) + _get_screens_origin();
		Size2 size = screen_get_size(cs);
		wd.fullscreen = true;
		wd.maximized = false;
		wd.minimized = false;
		_update_window_style(p_window, false);
		MoveWindow(wd.hWnd, pos.x, pos.y, size.width, size.height, TRUE);
		
		
		SystemParametersInfoA(SPI_GETMOUSETRAILS, 0, &restore_mouse_trails, 0);
		if (restore_mouse_trails > 1) {
			SystemParametersInfoA(SPI_SETMOUSETRAILS, 0, 0, 0);
		}
	}
}
DisplayServer::WindowMode DisplayServerWindows::window_get_mode(WindowID p_window) const {