[NO GBP] fixes some silly stairs slipups (#70628)

Two things:
Stone stairs didn't actually line up, not a soul would have noticed because mappers probably aren't gonna use it for a while, but I fixed it anyways.

Second, you could still build mat datum stairs freely without the whole frame system, invalidating its existence, so I've fixed that too. You can still build mat datum stairs, you just need a stairs frame made of iron or wood first.

code/controllers/subsystem/materials.dm

@@ -31,7 +31,6 @@ SUBSYSTEM_DEF(materials)
 	///List of stackcrafting recipes for materials using rigid recipes
 	var/list/rigid_stack_recipes = list(
 		new /datum/stack_recipe("Carving block", /obj/structure/carving_block, 5, one_per_turf = TRUE, on_solid_ground = TRUE, applies_mats = TRUE),
-		new /datum/stack_recipe("Material Stairs", /obj/structure/stairs/material, 10, time = 10 SECONDS, one_per_turf = TRUE, on_solid_ground = TRUE, applies_mats = TRUE),
 	)
 
 ///Ran on initialize, populated the materials and materials_by_category dictionaries with their appropiate vars (See these variables for more info)