To support the serialization of v2 payloads, the current eccDerivedToken field in the _FLE2EncryptedPayloadCommon_t struct in mongocrypt-marking.c should be replaced by another _mongocrypt_buffer_t called serverDerivedFromDataToken.

Consequently, the _FLE2EncryptedPayloadCommon_cleanup() should be updated, and _mongocrypt_fle2_placeholder_common() will have to be changed to replace the derivation of the ECCToken with that of the serverDerivedFromDataToken.