Use AudioManager#getRingerMode instead of

AudioManager#getRingerModeInternal to decide whether to vibrate or not.

AudioManage#getRingerModeInternal is an API only useful for volume
controllers and will return incorrect result for Telecom when we query
if the vibration enabled or not in DND mode.

Bug: 237490346
Test: RingerTest, manually test it in DND mode
Change-Id: Id041ec1416ef515718bb47354facbd96c0e90cc7