Use actual Wifi subId when applying Network policies.

This CL updates Network policy application to check against a Wifi
Network's actual subscription id (previously, all Wifi Networks appeared
to have subId INVALID_SUBSCRIPTION).

Bug: 178501049
Test: atest FrameworksVcnTests
Change-Id: I83f51e3351940bbb791bcc40bc75fe04baf68171
1 file changed