Add checks for known red herring in logs

There's some error messages in the logs that are red herrings that generate tickets with customers concerned about it. The biggest example I can give is the ERROR: duplicate key value violates unique constraint "namespace_aggregation_schedules_pkey" in the postgresql/current logs.

The issue for this error was opened 4 years ago: gitlab-org/gitlab#195427 and based on Stan's comment, this error is harmless.

Doing a quick search in Zendesk for this error message, I see that there's at least 72 tickets opened with that string.