add a convenient API

Yuhang Zhao

2023-12-19 f9aa4aacae56e3a82bce492196ff1802f3ecaf02

 src/quick/quickwindowagent.cpp

@@ -32,9 +32,7 @@
            return false;
        }

        if (!d->setup(window, new QuickItemDelegate())) {
            return false;
        }
        d->setup(window, new QuickItemDelegate());
        d->hostWindow = window;

#ifdef Q_OS_WINDOWS