Merge #2898

2898: take care of sieve too r=nextgens a=nextgens

## What type of PR?

bug-fix

## What does this PR do?

This is a follow-up to #2895 sieve can also trigger the rate limit... and a stack-trace.

### Related issue(s)

## Prerequisites
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [ ] In case of feature or enhancement: documentation updated accordingly
- [ ] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/workflow.html#changelog) entry file.


Co-authored-by: Florent Daigniere <nextgens@freenetproject.org>
Co-authored-by: Florent Daigniere <nextgens@users.noreply.github.com>

core/admin/mailu/internal/nginx.py

@@ -24,7 +24,8 @@ STATUSES = {
         "imap": "LIMIT",
         "smtp": "451 4.3.2",
         "submission": "451 4.3.2",
-        "pop3": "-ERR [LOGIN-DELAY] Retry later"
+        "pop3": "-ERR [LOGIN-DELAY] Retry later",
+        "sieve": "AuthFailed"
     }),
 }