fix: [stix import] Avoided import of empty header description
fix: [stix import] Avoided import of empty header description

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