Adding callback for setPreferredDataSubscriptionId.

The purpose is to provide a way to return success or failure upon
switching data to CBRS subscription.
The same callback is used for ONS to call internal API. Later it
will also be used by Carrier apps to call TelephonyManager#
setPreferredOpportunisticDataSubscription.

Bug: 122255288
Test: manual

Change-Id: Id3f43e024c902d6785017e7866f9e804a486b04f