Check for strlen instead of null for Maniphest title
Summary: Fixes T12744. Unclear why null doesn't work here but does for the title, but !strlen seems to work fine in both cases.
Test Plan: Create a new task, check mail folder, see [Created]
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin
Maniphest Tasks: T12744
Differential Revision: https://secure.phabricator.com/D18002