The Schnorr signature(s) (hex-encoded).
The message to verify.
The Cashu P2PK public key(s) (hex-encoded, X-only or with 02/03 prefix) to check.
The minimum number of unique witnesses required; at least 1.
True if the witness threshold was reached, false otherwise (a threshold below 1 included, which no set of witnesses can satisfy).
Checks enough unique pubkeys have signed a message.