fix: [stix import] Fixed missing event fields import
fix: [stix import] Fixed missing event fields import

- Such as event info, event date and so on

SteveClement/MISP,FloatingGhost/MISP,FloatingGhost/MISP,SteveClement/MISP,MISP/MISP,SteveClement/MISP,MISP/MISP,FIRSTdotorg/MISP,Rafiot/MISP,Rafiot/MISP,FIRSTdotorg/MISP,FIRSTdotorg/MISP,SteveClement/MISP,FloatingGhost/MISP,Rafiot/MISP,MISP/MISP,FIRSTdotorg/MISP,MISP/MISP,Rafiot/MISP,FloatingGhost/MISP,MISP/MISP,SteveClement/MISP