Do not make sound for notifications <= IMPORTANCE_DEFAULT in Android Auto.

To reduce distraction, if there is no heads-up notification, there should be no sound.

Fix: 119640453
Test: runtest -x frameworks/base/services/tests/uiservicestests/src/com/android/server/notification/BuzzBeepBlinkTest.java

Change-Id: Ie3280fb8239dd0779a3597aa75518f2ce9bdda58
2 files changed