Additional information for cleaning up eventing data

### Version Information

Server Version: N.A
CLI Version (for CLI related issue): N.A

### Environment

### What is the expected behaviour?
Report from a user when following https://hasura.io/docs/latest/graphql/core/event-triggers/clean-up.html

```
The job eventually completed, but it then started a very long AUTOVACUUM that created Transaction Logs that ate up all the database.

I ended up doing

truncate hdb_catalog.event_invocation_logs, hdb_catalog.event_log;

Which was much faster and prevented the AUTOVACUUM from running.

```

Start with the event-trigger cleanup page at https://hasura.io/docs/latest/graphql/core/event-triggers/clean-up.html and review the reported behavior involving hdb_catalog.event_invocation_logs and hdb_catalog.event_log. Clarify the cleanup guidance and document the relevant database implications, with the page updated to address the report.

Written by the indexing model from the issue text.