Several connectivity fixes

 - request network in the background and add a timeout
 - do not request network while holding the session lock
   as this can make the apps unresponsive
 - tie the launcher visibility to the virtual device instead
   of the connection status

Bug: n/a
Test: manual
Change-Id: I5ae37eacbbf133895f9a4cce13a5cc9b887ce0b9