Replay the most recent webhook event for a test case.

<b>Collection Partner API only</b> — this endpoint is a convenience stopgap that existed before GET /webhooks/events was available. It remains here for backward compatibility and because it is a thin wrapper over POST /webhooks/events/{eventId}/replay.

         <b>Design note:</b> This endpoint was added when the Collection Partner API had no
         delivery-history endpoint (`GET /webhooks/events`), making it impossible to look up
         event IDs for replay. It is a stopgap: "give me the last event without having to know its ID."
         Now that `GET /webhooks/events` exists, integrators can use the full
         history + replay-by-id pattern instead. This endpoint is intentionally <b>not</b> ported
         to the Customer API — the stopgap only exists because it was needed before history existed.