Floss: return codec info for hfp_audio_state

The audio stack needs a way to learn about the final codec selected,
which could be variable until SCO is created, thus we pass this value on
query of the audio state.

Bug: 241202081
Tag: #floss
Test: Build and verify codec info is returned

Change-Id: I17be8a027577e6fb2e068331e849d1d56101dd67