Expose DataSpecificRegistrationState as System API

  LteVopsSupportInfo is currently not accessible for telephony
  APK since DataSpecificRegistrationState is @hide api. This info is
  required to determine if current LTE network support IMS. This
  change exposes DataSpecificRegistrationState and LteVops info
  as System API.

Bug: 112194535
Test: atest

Change-Id: Iec5c42ccef88b66c3f8ef05f8f96b2a4133ca63f