message: Use OCamlBytes instead of String to avoid utf8 validation
diff: @@ -65,11 +65,11 @@ unsafe impl FromOCaml<ApplyBlockResponse> for ApplyBlockResponse {
  fn from_ocaml(v: OCaml<ApplyBlockResponse>) -> Self {
  unpack_ocaml_block! { v =>
  ApplyBlockResponse {
  - validation_result_message: String,
  + validation_result_message: OCamlBytes,
  context_hash: OCamlContextHash,
  - block_header_proto_json: String,
  - block_header_proto_metadata_json: String,
  - operations_proto_metadata_json: String,
  + block_header_proto_json: OCamlBytes,
  + block_header_proto_metadata_json: OCamlBytes,
  + operations_proto_metadata_json: OCamlBytes,
  max_operations_ttl: OCamlInt,
  last_allowed_fork_level: OCamlInt32,
  forking_testchain: bool,
  