Set active stream when progerss changed by user

When talkback is on, the volume seekbar can be selected
and changed via the hardware buttons. In this case,
set the active stream to the current stream that the user
is changing the volume of.

Test: manual
Fixes: 79719663
Change-Id: I45256001ca99d9b90ebaf89543d38aaf2fc8a401
1 file changed