Conpherence - smooth out user interaction switching threads in the durable column

Summary: Ref T7014. This changes the title and selected icon right as the user clicks it. This could maybe be in the "willLoadThread" callback hook, but it doesn't happen every time we load a thread, just this time so keep it right in the listener for now.

Test Plan: switched some threads and liked what I saw

Reviewers: epriestley, chad

Subscribers: Korvin, epriestley

Maniphest Tasks: T7014

Differential Revision: https://secure.phabricator.com/D12043