fix compilation error

Fixes: #211

include/FramelessHelper/Widgets/private/widgetssharedhelper_p.h

@@ -69,15 +69,8 @@ Q_SIGNALS:
     void micaEnabledChanged();
 
 private:
-#if (QT_VERSION < QT_VERSION_CHECK(5, 15, 0))
-    // Due to a Qt bug, we can't initialize the QPointer objects with nullptr.
-    // The bug was fixed in Qt 5.15.
     QPointer<QWidget> m_targetWidget;
     QPointer<QScreen> m_screen;
-#else
-    QPointer<QWidget> m_targetWidget = nullptr;
-    QPointer<QScreen> m_screen = nullptr;
-#endif
     bool m_micaEnabled = false;
     MicaMaterial *m_micaMaterial = nullptr;
     QMetaObject::Connection m_micaRedrawConnection = {};