fix: [attribute:simpleAddMalwareSample] Typo in loading `Object` class. Fix #5864
fix: [attribute:simpleAddMalwareSample] Typo in loading `Object` class.
Fix #5864

- Was not spotted before because the fixed line was if fact doing
nothing as the class's key was already used

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