Magic Mania 1⅔: Fixes #4335

Fixes #4335

Readds the 1/12 chance of stumbling out the bolt of change fully human with no mutantrace. It must have gotten lost during the mutantrace datumizing
actually I'm not sure how this works. You are effectively doing this:

var/datum/species/new_species = "[temp.type]"

How the hell is this valid? You are assigning a string to a datum.