1. Previously, getDnsNetId doesn't handle all the cases. Fix it with cosidering bypass private DNS flag. 2. Make getDnsNetId return Network instead of netId, and change name from getDnsNetId to getDnsNetwork Bug: 129530368 Test: atest DnsResolverTest DnsUtilsTest Change-Id: Ic8d45b802d72a266f9ec97bfea620c1ede6967e5