Removes hacky code in favour of a process() check for the nuke disk's location

Instead of having a lot of hacky checks to prevent the disk from leaving the Z-level, it will be checked periodically by process() if Z > 2

code/game/objects/structures/morgue.dm

@@ -240,10 +240,6 @@
 			return
 
 	else
-		if(!isemptylist(src.search_contents_for(/obj/item/weapon/disk/nuclear)))
-			usr << "You get the feeling that you shouldn't cremate one of the items in the cremator."
-			return
-
 		for (var/mob/M in viewers(src))
 			M.show_message("\red You hear a roar as the crematorium activates.", 1)