Floss: print logs to show absolute volume support

Even when AVRCP is connected, absolute volume support may not be
correctly propagated, and we do not have a good way to see that with the
current logs.

In this CL, we add the logs to show that value on AVRCP connection.

Bug: 254313937
Test: Deploy and verify
Tag: #floss

Change-Id: I942fea43f48ed206a6daa91cb5f472af7a0ce34b