Remove deprecateStreamTypeForPlayback from HwAudioSource

It used to be there to hide from API list, and since it's been addressed
in PlayerBase, this pseudo override is no longer needed.

Bug: 126702177
Test: make system-api-stubs-docs-update-current-api
Change-Id: I8caa75410d1ffb2b0e690a82396ac978b03a2844