Fixed that data unthrottling not working

The data unthrottling input from data service
is APN name, not APN type. DcTracker should convert
APN to APN types before sending unthrottling information
to data throttler.

Fix: 182885625
Test: atest DcTrackerTest#testDataUnthrottled
Merged-In: I32ad58bb01671cf4c19923cb3010cb5201c86d14
Change-Id: I32ad58bb01671cf4c19923cb3010cb5201c86d14
(cherry picked from commit 71164c8d)