fix: [stix2 export] Fixed x509 object export
fix: [stix2 export] Fixed x509 object export

- x509 fingerprint hashes parsing was pointing to
  a part of a mapping dict which does not exist

MISP/MISP,SteveClement/MISP,MISP/MISP,MISP/MISP,MISP/MISP,SteveClement/MISP,MISP/MISP,SteveClement/MISP,SteveClement/MISP,SteveClement/MISP