Make Phame Header and Profile Image Transactional

Summary: Ref T9360. This makes these transactional.

Test Plan: Set new header, delete header. Set new profile image, reset profile image.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T9360

Differential Revision: https://secure.phabricator.com/D16217