Trim transaction overload when converting events from all-day and back
Summary: Closes T8136, Trim transaction overload when converting events from all-day and back
Test Plan: Create new event, save, edit, change to all-day, save, remove all-day flag, save. Feed should not show "end date changed" transaction
Reviewers: #blessed_reviewers, epriestley
Reviewed By: #blessed_reviewers, epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T8136
Differential Revision: https://secure.phabricator.com/D12781