Report the shopper's answer to a soundbite recognition

After a soundbite answer with recognition.confidence PROBABLE, the wallet asks the shopper "Is this the ad?" and reports the answer here, with the recognition.id of that answer. Measurement only: nothing is stored and nothing about the transaction changes. Send it fire-and-forget; a failure must never reach the shopper. Restricted to active banks. Accepts the recognition-only token ("scope": "soundbite") described on POST /api/transactions, and like it is answered only at the soundbite hosts: api.payware.eu and sandbox.payware.eu refuse it with 421 ERR_SOUNDBITE_HOST.