Separate user enabled and user allowed

When the preferred data on backup phone,
- before the change, due to service state change race condition, if service state change event reaches switch controller first, the phone will immediately switch back to the default because it thought data is now allowed due to non-service state change reason.
- after the change, we ensure only immediately switch back when user
  disabled the settings. For other environment related reasons, we allow
a stability check.

Also, this change remove the ratss flag which is 100% rolled out to
prune branches

Fix: 338552223
Test: voice call + data browsing
Test: atest rameworks/opt/telephony/tests/telephonytests/src/com/android/internal/telephony/data/AutoDataSwitchControllerTest.java

Change-Id: Ib413236991f7d64043973c355ff88779543dee9e