Define IConnectivityDiagnosticsCallback aidl.

IConnectivityDiagnosticsCallback is defined for making Binder calls out
of ConnectivityService to client implementations of
ConnectivityDiagnosticsCallback.

Bug: 143187964
Test: compiles
Change-Id: I68dd1afddaed21528a60c2b6f0add34d0bec8242
1 file changed