itachi isnt out of edo tensei hes just out of kabutomarus control due to the crow and shishuis genjutsu , however if kabutomaru were to end the edo summons then itachi would also be released from edo tensei and thus die
But Itachi destroyed shisui eye?. And it's not that easy cause why would kabuto unsummon Itachi cause there must be a prob that if he do that he unsummons all