[Core] Enemy Matrix Issues

need to add an all-enemies list to draw from if no enemies found in valid singles, and add in enough enemies of the missing types to only be swapped into spots the other enemies are requiring

also need to maybe allow this for enemies that run out of slots too, as in when the matrix is configured so swap enemies with other enemies that appear more or less often, such that there is a variance

not_randomized not excluded from randomization when found