AVRCP ignore duplicate volume changed notifications

If two volume changes come in quickly only the first one has its
absolute volume changed notification blocked.  Update code to keep track
of how many requests were received recently and block all of them.

Bug: 77526454
Test: Stream music and hold volume up/down on phone.
Change-Id: Ibc96050ed1ed536da568c2d6917bfeb5a851b84e