Fix issue where video does not un-pause after call waiting dismissed.

When an incoming call waiting call is received, the VideoPauseController
sends a "pause" command to the video provider.
However, upon dismissing the call waiting call, the foreground call
was not being unpaused.

Bug: 21815566
Change-Id: I637ab70d1b2adf4510dd87e5d56e233b1a3e065d