message: Delete duplicate string
  Looks like there was a duplicate upstrea_rq_time string with no postfix `_`.
diff: @@ -60,7 +60,6 @@ private:
  const absl::string_view internal_upstream_rq_{"internal.upstream_rq_"};
  const absl::string_view upstream_rq_completed_{"upstream_rq_completed"};
  const absl::string_view upstream_rq_time_{"upstream_rq_time"};
  - const absl::string_view upstream_rq_time{"upstream_rq_time"};
  const absl::string_view upstream_rq_{"upstream_rq_"};
  const absl::string_view vcluster_{"vcluster"};
  const absl::string_view vhost_{"vhost"};
  