Fill in each dns stats value in message NetworkDnsEventReported

Result dump
metric_id: 1111
event_metrics {
  data {
    elapsed_timestamp_nanos: 166844290056
    atom {
      network_dns_event_reported {
        event_type: EVENT_GETADDRINFO
        return_code: RC_EAI_NO_ERROR
        latency_micros: 78961
        hints_ai_flags: 1024
        res_nsend_flags: -1
        network_type: NT_UNKNOWN
        private_dns_modes: PDM_STRICT
        dns_query_events {
          dns_query_event {
            rcode: NS_R_NO_ERROR
            type: NS_T_A
            ip_version: IV_IPV4
            protocol: PROTO_DOT
            dns_server_index: 0
            latency_micros: 77843
          }
        }
      }
    }
  }

Bug: 119862317
Test: ./out/host/linux-x86/bin/statsd_testdrive 116
Change-Id: Ia9d2ca076cdd95df206f573531a17badb34fda62