Get UUID from TrackChanged event before quary item attribute

Add missing UUID assignment when handling changed of
AVRC_EVT_TRACK_CHANGE so stack can quary for correct item.

Bug: 223088379
Test: atest net_test_btif_rc:BtifRcTest#handle_track_change_notification_response
Flag: EXEMPT, Bug fix
Change-Id: I8dd13a3b381d76901e0b6b1b77103c5789eee0f8