Add TRANSPORT_USB and freeze DnsResolver aidl

This change only modified IDnsResolver.aidl and other files
are generated by "m dnsresolver_aidl_interface-{update,freeze}-api".

Bug: 181742019
Test: atest resolv_unit_test resolv_stats_test_utils_test \
      resolv_integration_test resolv_stress_test resolv_gold_test
Change-Id: Ie45c2429959bf5098c8f3857e721f44ff203eafd