Non-deterministic facedir for craft output

Craft output nodes are rotate in a random (but still
upright) direction if they're facedir, and the param2
is not specified by the recipe.  Currenly only affects
optic prisms.

docs/issues-game.txt

@@ -17,9 +17,6 @@ ISSUES-GAME: Gameplay-affecting issues
 	  rather than pre-material?
 	- https://discord.com/channels/507234450615042048/507234451085066248/963498043708178522
 
-- Facedir nodes should get a random facedir (top-up, random cardinal
-  orientation) after crafting.
-
 - /snuff should probably snuff torches too
 	- General snuffable/on_snuff API?
 	- Merge with growtrees for a general on_cheat API?

mods/nc_api_craft/craft_check.lua

@@ -144,8 +144,15 @@ local function craftcheck(recipe, pos, node, data, xx, xz, zx, zz)
 					nodecore.stack_set(p, ItemStack(""))
 				end
 				if r then
-					local n = minetest.get_node(p)
-					r.param2 = n.param2
+					if not r.param2 then
+						local rd = minetest.registered_nodes[r.name]
+						if rd and rd.paramtype2 == "facedir" then
+							r.param2 = math_random(0, 3)
+						else
+							local n = minetest.get_node(p)
+							r.param2 = n.param2
+						end
+					end
 					nodecore.set_loud(p, r)
 					nodecore.fallcheck(p)
 				end