Finish customize system button pos for QtWidgets

SineStriker

2023-12-27 2f2ee6571e9ce784db0488ade60816f09bd7448c

 examples/mainwindow/mainwindow.cpp

@@ -115,10 +115,6 @@
    windowAgent = new QWK::WidgetWindowAgent(this);
    windowAgent->setup(this);

#ifdef Q_OS_WIN
    windowAgent->setWindowAttribute(QStringLiteral("dark-mode"), true);
#endif

    // 2. Construct your title bar
    auto menuBar = [this]() {
        auto menuBar = new QMenuBar();