Evokers rarely summon Allays while summoning Vexes

Evokers should have a rare chance of summoning Allays while the Evoker is trying to summon Vexes. This makes Allays renewable and gives another use for the Evoker. Also I think a cool addition to add with this is that Allays heal Evokers same as they heal themselves. This will make Evoker more challenging and in return more challenging to get a Totem of Undying. This addition won't make a player get Allays very easily since Evokers are pretty dangerous and they will only spawn Allays rarely.