Conpherence - hide file transactions

Summary: added support for when showHide is true AND set showHide to true for Files.

Test Plan: loaded a conpherence and saw no more "updated files" transacations

Reviewers: chad, epriestley

Reviewed By: chad

CC: aran, Korvin

Maniphest Tasks: T2399, T2411

Differential Revision: https://secure.phabricator.com/D4649