Replaced DcRequest with TelephonyNetworkRequest

DcRequest should be replaced by TelephonyNetworkRequest,
which also supports priority. This is the preliminary
step before removing com.android.internal.telephony.dataconnection.

Bug: 196597630
Test: atest FrameworksTelephonyTests
Change-Id: Id94556178ce18d003e312b9e16e1cbaee83f7d97