Fix issue where upgrade request UX does not show.

+ adding back CallList listener to handle the onUpgradeToVideo event.
This was removed when InCall fragments were refactored (before the
onUpgradeToVideo method existed) in mnc-dev; meanwhile in m-wireless-dev
the new onUpgradeToVideo listener was added.

Bug: 21850707
Change-Id: I85df2feee5094bdde530cf810da3930745897b4d