fix: [stix2 export] Fixed file object references with its contained data object
fix: [stix2 export] Fixed file object references with its contained data object

SteveClement/MISP,SteveClement/MISP,MISP/MISP,FIRSTdotorg/MISP,Rafiot/MISP,FloatingGhost/MISP,FIRSTdotorg/MISP,FIRSTdotorg/MISP,MISP/MISP,devnull-/MISP,devnull-/MISP,MISP/MISP,FIRSTdotorg/MISP,MISP/MISP,MISP/MISP,Rafiot/MISP,FloatingGhost/MISP,SteveClement/MISP,SteveClement/MISP,FloatingGhost/MISP,SteveClement/MISP,Rafiot/MISP,devnull-/MISP,FloatingGhost/MISP,devnull-/MISP,Rafiot/MISP