Context

Track PR #2430
Provide a more meaningful error message.

Definition of done

Propagate the error with the BSON type rather than the Golang type.

Pitfalls

Does libmongocrypt validate that key document _id fields are binary UUIDs and silently skip documents that don't match?
_id can never be non-binary in the documents that reach setRewrapManyDataKeyWriteModels from libmongocrypt. The check !id.BinaryOK() is unreachable dead code.