Fix Cyst Burst improperly copying diseases

This fixes a pretty serious bug where diseases using effectTemporaryValue instead of addTemporaryValue can error when copied by Cyst Burst and cause their temp values to be permanent. This doesn't effect most if any of the vanilla diseases, I only noticed it because of a Cults one which can just be rewritten for now. Should be safe to leave this for 1.6 but figured I'd put it up now.