Keep track number in sync when playlist has the same song many times

As it stands, track updates from the media framework will not be
communicated to remote device if the track name, artist and album are
the same. As a result, a playlist with the same track many times in a
row won't end up sending that updated information unless the remote
device itself decides to request metadata again on its own.

This tiny change will cause us to send a track changed even any time we
(1) Change to the same track that occurs multiple times in a playlist
(2) Change to the same track in a different spot in a new playlist

Tag: #stability
Bug: 163720233
Test: atest BluetoothInstrumentationTests
Change-Id: I401d4a5dc08f992ab75382545108b3be110040fb