Windows QPA: Accept foreign windows when checking for wheel receivers

After change 14efcaa392, foreign
windows no longer have a corresponding QWindowsWindow. This should
not block wheel events when checking for blocking modal windows.

Amends change 14efcaa392.

Task-number: QTBUG-54430
Change-Id: I1ac87445844946bafc214024e27da08c4f884d79
Reviewed-by: Tim Blechmann <tim@klingt.org>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

src/plugins/platforms/windows/qwindowsmousehandler.cpp

@@ -393,6 +393,8 @@ static bool isValidWheelReceiver(QWindow *candidate)
 {
     if (candidate) {
         const QWindow *toplevel = QWindowsWindow::topLevelOf(candidate);
+        if (toplevel->type() == Qt::ForeignWindow)
+            return true;
         if (const QWindowsWindow *ww = QWindowsWindow::windowsWindowOf(toplevel))
             return !ww->testFlag(QWindowsWindow::BlockedByModal);
     }