Fix race condition that was preventing "Voice Call" menu from reliably calling.

The code attempted to do a call to a session immediately after a call that
launched a coroutine to set up a session.  Sometimes, the coroutine executed
in time, sometimes not.

The fix is to set a flag to start a call after the session has been created
on the server.

Test Plan:
* Close all active chat sessions.
* Select 'Voice Call' in the context menu of a nearby avatar.
* Validate popup appears for that nearby avatar requesting to start/ignore/go to im.
* Select 'start'
* Validate the call completes.

0 files changed, 0 insertions, 0 deletions