Move Conpherence to "Z" monogram instead of "E"
Summary:
Ref T7439. Fixes T7438. This is only used in email right now.
Remain backward compatible.
Test Plan:
- Sent a message, saw a "Z" reply address.
- Checked the PHIDType.
- Grepped for "E" and 'E'.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: epriestley
Maniphest Tasks: T7439, T7438
Differential Revision: https://secure.phabricator.com/D11956