Change data connection state logic

This changed the logic of DcTracker.getState(apnType), returned the
DataState of the given apn type based on the DataConnection rather than
the ApnContext.

Test: runtest -x DcTrackerTest -m testGetDataConnectionState
Bug: 65637583
Change-Id: Ibe5a8a3690db99050a19357e38e5d3f18e2f6ee9