Bluetooth in band ring

Prevent the telecom service from generating a ringer if there is already
a ringer generated by a phone connected over bluetooth headset client
service.

Bug: 65673832
Test: runtest telecom-unit -c
com.android.server.telecom.tests.RingerTest

Change-Id: I40710787cab0215f0456153a3557aa8cf1a50cdf
(cherry picked from commit 40ea5eea)