AVRCP: UID_CHANGED response for GetItemAttributes

When we receive a GetItemAttributes command with the wrong UID counter
attribute, we should respond with UID_CHANGED.  Currently our UID
counter never changes from 0, but it may in the future.

Bug: 62924455
Test: PTS test AVRCP/TG/MCN/CB/BI-05-C
Change-Id: I98b6dd879019b04c695c8dc28afab88ae0e05175
(cherry picked from commit 45551315)