Throw exception for sharing group if unauthorised user
Throw exception for sharing group if unauthorised user

Instead of returning a false value for sharing_group_id, throw an exception if user is not authorised to save modifications to that sharing group.
SteveClement/MISP,FIRSTdotorg/MISP,Rafiot/MISP,MISP/MISP,MISP/MISP,cristianbell/MISP,Rafiot/MISP,TheDr1ver/MISP,devnull-/MISP,SteveClement/MISP,SteveClement/MISP,FIRSTdotorg/MISP,MISP/MISP,RichieB2B/MISP,devnull-/MISP,FloatingGhost/MISP,RichieB2B/MISP,FIRSTdotorg/MISP,TheDr1ver/MISP,crruthe/MISP,SteveClement/MISP,FIRSTdotorg/MISP,devnull-/MISP,MISP/MISP,FloatingGhost/MISP,RichieB2B/MISP,devnull-/MISP,crruthe/MISP,SteveClement/MISP,TheDr1ver/MISP,RichieB2B/MISP,cristianbell/MISP,MISP/MISP,crruthe/MISP,Rafiot/MISP,FloatingGhost/MISP,cristianbell/MISP,Rafiot/MISP,crruthe/MISP,cristianbell/MISP,TheDr1ver/MISP,FloatingGhost/MISP