ARI: Allow usage of ASYNCGOTO with Stasis()

ARI: Allow usage of ASYNCGOTO with Stasis()

When the AMI Redirect action is used with a channel bridged inside
Stasis() and not running a pbx, the channel is hung up instead of
proceeding to the desired location in dialplan. This change allows
such channels to be Redirected properly by detecting the operation
used by Redirect (ASYNCGOTO) and using the code already established
for functionality of the ARI channel continue operation.

ASTERISK-24591 #close
Review: https://reviewboard.asterisk.org/r/4271/

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@430355 65c4cc65-6c06-0410-ace0-fbb531ad65f3