Remove JobInfo usage of NetworkRequest#networkCaps

NetworkRequest#networkCapabilities is an implementation detail (not part
of the NetworkRequest API); NetworkRequest has getters that return the
same information.

Bug: 174436414
Bug: 142281756
Test: m
Merged-In: I47e7ab1b887b2fe2dddef223bd7c66bdd290fc56

Change-Id: I47e7ab1b887b2fe2dddef223bd7c66bdd290fc56