message: Monitoring: Remove Prometheus UI link from sidebar
  Also rename the "Query Browser" sidebar item to "Metrics".
diff: @@ -45,19 +45,16 @@ const monitoringNavSectionStateToProps = (state) => ({
  canAccess: !!state[featureReducerName].get(FLAGS.CAN_GET_NS),
  grafanaURL: state[monitoringReducerName].get(MonitoringRoutes.Grafana),
  kibanaURL: state[monitoringReducerName].get(MonitoringRoutes.Kibana),
  - prometheusURL: state[monitoringReducerName].get(MonitoringRoutes.Prometheus),
  });
  -const MonitoringNavSection_ = ({grafanaURL, canAccess, kibanaURL, prometheusURL}) => {
  +const MonitoringNavSection_ = ({grafanaURL, canAccess, kibanaURL}) => {
  const showAlerts = canAccess && !!window.SERVER_FLAGS.prometheusBaseURL;
  const showSilences = canAccess && !!window.SERVER_FLAGS.alertManagerBaseURL;
  - const showPrometheus = canAccess && !!prometheusURL;
  const showGrafana = canAccess && !!grafanaURL;
  - return showAlerts || showSilences || showPrometheus || showGrafana || kibanaURL
  + return showAlerts || showSilences || showGrafana || kibanaURL
  ? <NavSection title="Monitoring">
  {showAlerts && <HrefLink href="/monitoring/alerts" name="Alerting" startsWith={monitoringAlertsStartsWith} />}
  - {showAlerts && <HrefLink href="/monitoring/query-browser" name="Query Browser" />}
  - {showPrometheus && <ExternalLink href={prometheusURL} name="Metrics" />}
  + {showAlerts && <HrefLink href="/monitoring/query-browser" name="Metrics" />}
  {showGrafana && <ExternalLink href={grafanaURL} name="Dashboards" />}
  {kibanaURL && <ExternalLink href={kibanaURL} name="Logging" />}
  </NavSection>
  