Prevent updating now playing queue unnecessarily

In our current implementation, we send a "now playing list updated" event each
time the track changes in the queue due to the way we compare the queues.
This patch will eliminate this by comparing the media permanent metadata
instead.

Bug: 346730065
Test: atest BluetoothInstrumentationTests
Flag: Exempt trivial
Change-Id: I3e449d632eb2b92bffd8d939da8f6704400cad40