Define callback for network tested with extras.

A new callback function is defined in INetworkMonitorCallbacks for
alerting ConnectivityService of a network test result along with a
PersistableBundle of extras.

Bug: 143187964
Test: compiles
Test: atest NetworkStackTests
Change-Id: Id07eda28f970e5423b323072d0639e77c8e6bd2e
Merged-In: Id07eda28f970e5423b323072d0639e77c8e6bd2e