feat(server): log warning when max request limit is exceeded

[vvanglro]

Summary

ref: #2412

We can't exactly limit the number of requests #2420, so at least we can have a friendly reminder log after meeting the limit.

Checklist

• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.