chg: Return the sighting when adding one through REST API
chg: Return the sighting when adding one through REST API

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