Update CarrierPrivilegesTracker to cache package names

This information will be used in follow-up CLs to provide the backing
for faster TelephonyManager method implementations. For now, we just
update the internal data that gets cached; the binder calls in
PhoneInterfaceManager will be updated to point to CPT in follow-ups.

Bug: 205736323
Test: atest com.android.internal.telephony.CarrierPrivilegesTrackerTest
Change-Id: I05ae40680f94829aa72ffebd14764831994d2b21