Group chat flyout support

* Moved the flyout message extraction code into BubbleViewInfo task thing
  since it's where we extract info etc
* FlyoutMessage object contains anything we might display in the flyout
  including avatar, name, message, and isGroupChat
* If we have an avatar & group chat is yes then we show the avatar

I'll need to do a follow up CL where we get the "generated" avatars
for group chats where the developer hasn't set an explicit avatar for
the person.

Bug: 138258523
Test: manual with test app
Change-Id: Ie326b5354ce5f9268ef58c2f67cdecc3df0bf4e4