ConnectivityService would be centralized location for deciding local
network so for this effort passing isLocalRoute parameter to
routecontroller in netd for route addition, removal and modification.
Bug: 394308861
Test: Manually tested.
Test: atest ConnectivityCoverageTests
Test: atest ConnectivityCoverageTests:android.net.connectivity.com.android.server.connectivityservice.CSLocalRouteTest
Test: atest netd_integration_test
Flag: EXEMPT Using device config kill-switch
Change-Id: I9f11882665375bba10fa369c2e25f374b5e63661