Update InvitationListener.php
Update InvitationListener.php

Addressing comment https://github.com/ZiNETHQ/spark-invite/commit/ab31cff1baacddeb6f13a7f30d4672f4f0d15ce9#commitcomment-21868929 (quite right, thanks!)
ZiNETHQ/spark-invite,ZiNETHQ/spark-invite