Returns a ready-to-sign transaction that closes a live ERC-721 SeaDrop V1 drop by replacing its stages with one that has already ended. Only the collection owner can call this endpoint, and the transaction must be sent from from.

This saves that ended stage as the drop's draft before returning, replacing any edits saved with POST /api/v2/drops/{slug}. If the transaction is never sent, save new edits before publishing again.