Activate Telephony Service Handle Caching

The infrastructure for telephony handle caching was checked in in
ag/10255108, but disabled due to changes that needed to be made in AOSP.
This CL activates the caching.

Test: atest PhoneSubInfoControllerTest
Test: atest DcTrackerTest
Test: atest CellBroadcastConfigTest
Bug: 140788621
Change-Id: I42c829a07f9192ccbedef38e835019804eb20978