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 Merged-In: Ibb5080acd3c296650d56532fc7da525e9fa95e8f (cherry picked from commit 3854966dc9499e39187835606397b16367e5e27b) Change-Id: I37353642088bcc17da0cf17f78a5ed9efc9aefc3