fix: [stix2 export] Catching errors that could happen with custom tags
fix: [stix2 export] Catching errors that could happen with custom tags

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