Build A Spell Fix

Build A Spell Fix: the Builder's update

OK I'm very excited about this one. This changes the Wall spell component to behave more like an actual wall: it is by default 1 block thick, and the width and height are determined by the setting of the Conjure spell component's expandRadiusBase in the effects config. To increase the thickness, you add the increasedArea component. Adding the Fill component will create a very large and wide wall that's still only 1 block thick (unless you also add increasedArea). I also made a datapack that adds slabs and wall blocks to the whitelist of blocks you can use with Conjure, which I'll upload separately.