Conpherence - get the durable column header actions working correctly

Summary:
Ref T7014. This diff addresses

• getting it to be the right set of options
  • add participant
  • view in conpherence
  • close window
• making those options work
• make it so if you are on /conpherence/ you can't toggle the durable column

Test Plan: inspected dom via chrome tools and found last transaction. added a participant and inspected the single new transactin added for accuracy. used view in conpherence action to view in conpherence. used close window action to close window

Reviewers: chad, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7014

Differential Revision: https://secure.phabricator.com/D11991