floss: avrcp: separate Play Pause events

Separate the Play and Pause events from the PlayPause combo event since
media information is in place. The peripheral device can now correctly
query media status to send out Play or Pause correspondingly.

Bug: 240780471
Tag: #floss
Test: local test with evtest
Change-Id: I0a7bbd8eaef6a57759ffb7b94e9282bd46924c9e