R1:8825a09f676a

Fix legacy crash when visiting Motivator backend as anon

Summary:
Now anonymous people can visit this page:

http://phorge.localhost/home/menu/new/custom/motivator/

And you do not see anymore this crash:

Undefined variable $custom_phid
phorge applications/search/engine/PhabricatorProfileMenuEngine.php : 61 PhutilErrorHandler::handleError()
phorge applications/search/engine/PhabricatorProfileMenuEngine.php : 916 PhabricatorProfileMenuEngine::getEditModeCustomPHID()…