### 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_
	ERR_FAIL_INDEX(p_shape, CURSOR_MAX);
	if (cursor_shape == p_shape) {
		return;
	}
	if (mouse_mode != MOUSE_MODE_VISIBLE && mouse_mode != MOUSE_MODE_CONFINED) {
		cursor_shape = p_shape;
		return;
	}
	static const LPCTSTR win_cursors[CURSOR_MAX] = {
		IDC_ARROW,
		IDC_IBEAM,
		IDC_HAND, 
		IDC_CROSS,
		IDC_WAIT,
		IDC_APPSTARTING,
		IDC_SIZEALL,
		IDC_ARROW,
		IDC_NO,
		IDC_SIZENS,
		IDC_SIZEWE,
		IDC_SIZENESW,
		IDC_SIZENWSE,
		IDC_SIZEALL,
		IDC_SIZENS,