DRAFT, recurring events need optional end dates
Summary: Ref T8357, DRAFT, recurring events need optional end dates
Test Plan: Edit recurring event, set end date, save, recurring ghosts should not generate after end date
Reviewers: #blessed_reviewers, epriestley
Reviewed By: #blessed_reviewers, epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T8357
Differential Revision: https://secure.phabricator.com/D13088