Add a new error for failure in auto-vacuum

What does this MR do and why?

I want to bring your attention to a recent emergency incident that can be accessed internally at this Zendesk link. During our investigation, we encountered an error message that read as follows: "ERROR: database is not accepting commands to avoid wraparound data loss in database 'gitlabhq_production'." However, we could not locate this specific error upon reviewing the logs. Instead, we identified a different error message: "ERROR: failed to re-find parent key in index 'XXX' for deletion target page XXX." We followed the established procedure to address this issue and successfully resolved the problem. I have included the details in our documentation repository to ensure the accurate documentation of this error and its corresponding resolution. It is important to note that the error mentioned above resulted in an exclusive lock on the table, thereby preventing the execution of the database migration process. This issue has been observed in several related tickets at this Zendesk search link. Given its recurrence, it would be beneficial to incorporate this error and its resolution into our documentation for future reference.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.