message: Monitoring Dashboards: Change "Refresh Interval" options
  Change some of the "Refresh Interval" dropdown options and also add an
  option for switching auto-refresh off.
diff: @@ -79,7 +79,8 @@ const AllVariableDropdowns = connect(
  const timespanOptions = ['5m', '15m', '30m', '1h', '2h', '6h', '12h', '1d', '2d', '1w', '2w'];
  const defaultTimespan = '30m';
  -const pollIntervalOptions = ['5s', '15s', '30s', '1m', '2m', '5m', '15m', '30m'];
  +const pollOffText = 'Off';
  +const pollIntervalOptions = [pollOffText, '15s', '30s', '1m', '5m', '15m', '30m', '1h', '2h', '1d'];
  const defaultPollInterval = '30s';
  // TODO: Dynamically load the list of dashboards
  @@ -276,7 +277,9 @@ const MonitoringDashboardsPage_: React.FC<MonitoringDashboardsPageProps> = ({
  title="Time Range"
  />
  <VariableDropdown
  - onChange={(v: string) => setPollInterval(parsePrometheusDuration(v))}
  + onChange={(v: string) =>
  + setPollInterval(v === pollOffText ? null : parsePrometheusDuration(v))
  + }
  options={pollIntervalOptions}
  selected={defaultPollInterval}
  title="Refresh Interval"
  @@ -327,7 +330,7 @@ type VariableDropdownProps = {
  type BoardProps = {
  board: string;
  patchVariable: (key: string, patch: Variable) => undefined;
  - pollInterval: number;
  + pollInterval: null | number;
  timespan: number;
  };
  @@ -338,7 +341,7 @@ type AllVariableDropdownsProps = {
  type CardProps = {
  panel: Panel;
  - pollInterval: number;
  + pollInterval: null | number;
  timespan: number;
  variables: VariablesMap;
  };
  