Revert "qt: Add ObjectInvoke template function"

This reverts commit 5659e73.

Author: hebasto

src/qt/guiutil.h

@@ -361,18 +361,6 @@ namespace GUIUtil
     #endif
     }
 
-    /**
-     * Queue a function to run in an object's event loop. This can be
-     * replaced by a call to the QMetaObject::invokeMethod functor overload after Qt 5.10, but
-     * for now use a QObject::connect for compatibility with older Qt versions, based on
-     * https://stackoverflow.com/questions/21646467/how-to-execute-a-functor-or-a-lambda-in-a-given-thread-in-qt-gcd-style
-     */
-    template <typename Fn>
-    void ObjectInvoke(QObject* object, Fn&& function, Qt::ConnectionType connection = Qt::QueuedConnection)
-    {
-        QObject source;
-        QObject::connect(&source, &QObject::destroyed, object, std::forward<Fn>(function), connection);
-    }
 
     /**
      * Replaces a plain text link with an HTML tagged one.