Conpherence - improve durable column performance when sending updates

Summary: Ref T7708. We were generating things like the files widget when users sent a comment. This is unnecessary if we are in minimal display mode. This saves us fetching some data + rendering.

Test Plan: sent messages successfully in durable column and full conpherence view

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7708

Differential Revision: https://secure.phabricator.com/D12760