migration voicemail settings to notificationChannel

- create voice mail notification channel when sim loaded
- migrate voicemial notification settings if subId matches, otherwise
fallback to predefined channel settings

Bug:62100344
Test: Manual test:
1. enabled voicemail notification vibration on NYC build.
2. update to OC build with notification channel
3. make sure user preference is not lost during system update.

Change-Id: I877d7271072e3a34d171bcb5b780c99cdb308929