Migrate ConnectivityManagerTest to callback rule

ConnectivityManagerTest has existing logic that is functionally
identical to AutoReleaseNetworkCallbackRule. Migrate it to use the rule
instead.

This just migrates callbacks to their Rule equivalents, except for
waitForActiveNetworkMetered which relied on the NetworkStack
ConnectivityManager shim for registerSystemDefaultNetworkCallback on R
to use a fallback implementation. Use the same NetworkRequest as
ConnectivityManagerShim as a direct fallback in this case.

Test: atest
Change-Id: I06501a5b7c05071667344bedb08e9b824c03b27c
2 files changed