Clean up mediabrowser callbacks

The test connection was not getting cleaned up properly, which is why
VLC's foreground notification stayed around. It also should have been
replaced with the actual resumption controls once those were ready.
At the same time Spotify was not restarting on the first tap because the
browser was being disconnected prematurely. So, if we have successfully
connected to restart, wait until the new session info has come in to
disconnect the browser.

Fixes: 154825715
Fixes: 155098687
Test: manual

Change-Id: I207ae4790e5ae2b073def1ceb654808907d5a5c4