text: Title: [alerting] event log errors when multiple event log resources
  Body: I noticed a wall of text when starting Kibana, and happening to have an old `.kibana-event-log` in my indices - we've since moved to using versions in the index name (eg, `.kibana-event-log-8.0.0'): https://gist.github.com/pmuellr/45a18addc7eb71a5634e673ee33a4197
  
  ~~Additionally, but may not be related, was unable to load the Kibana web ui, probably need to `yarn kbn bootstrap`, this from running some code I'd just pulled from GH - nothing logged in Kibana.~~ Narrator: it was `yarn kbn bootstrap`.
  
  This isn't really a bug in our code, per-se, since we're not expecting people to have multiple event log indices in a cluster, that aren't all managed by the event log plugin.  But perhaps it's an example of what could go wrong in a customer environment.
  
  Basically, just logging this to ponder over it, wondering how bad is this (I didn't investigate), and if it's not great, what can we do to remediate.