We seen issues with https://gracedb.ligo.org/superevents/S231102av/view/ where a hung `raven.update_coinc_far` changed the preferred external event info to before there was sky map info (not the correct behavior). This could have been fixed by calling this function by the `exttrig` worker which has a concurrency of 1. It could also make sense to call the parent function `raven.trigger_alert_alert` to only have one event trigger at a time and make the message calls more orderly.