message: Monitoring: Fix silence form bug where start defaulted to 2h from now
  Start time should default to the current time and the end time should be
  2h from now.
diff: @@ -1318,7 +1318,7 @@ const SilenceForm_: React.FC<SilenceFormProps> = ({ defaults, Info, title }) =>
  const [createdBy, setCreatedBy] = React.useState(defaults.createdBy ?? '');
  const [duration, setDuration] = React.useState(defaultDuration);
  const [endsAt, setEndsAt] = React.useState(
  - defaults.endsAt ?? formatDate(new Date(now.setHours(now.getHours() + 2))),
  + defaults.endsAt ?? formatDate(new Date(new Date(now).setHours(now.getHours() + 2))),
  );
  const [error, setError] = React.useState<string>();
  const [inProgress, setInProgress] = React.useState(false);
  