MediaSession2: Add playlist parameter supports

This CL implements following APIs:
 - MediaSession2.get/setPlaylistParams()
 - ControllerCallback.onPlaylistParamsChanged()

MediaController2.get/setPlaylistParams() is not implemented yet.

Bug: 72537520
Test: Passed MediaSession2Test
Change-Id: Iccbd8f5febb1abd86d8ff819bd611ca7217fb4e1
6 files changed