[XFA] Media Of The Month - XF2 4.5.1

Corrected bugs:

• InvalidArgumentException: Attempted to convert NULL to string/binary [username] src/XF/Mvc/Entity/Entity.php:688
• ErrorException: Fatal Error: Cannot use isset() on the result of a function call -> Leading to issues with thread notifications

Corrected bugs:

• ErrorException: Fatal Error: Cannot use isset() on the result of a function call src/addons/XFA/XFMGMediaOfTheMonth/Cron/XFMGMediaOfTheMonth.php
• ErrorException: Fatal Error: Cannot use isset() on the result of a function call src/addons/XFA/XFMGMediaOfTheMonth/Cron/XFMGMediaOfTheMonth/Listener.php

Modification:

• [XFA] Core min. version requirement changed to 1.5.1