SPIGOT-5245: Unneeded cast to WorldNBTStorage in CraftWorld#getWorldFolder

By: md_5 <git@md-5.net>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftWorld.java

@@ -1778,7 +1778,7 @@ public class CraftWorld implements World {
 
     @Override
     public File getWorldFolder() {
-        return ((WorldNBTStorage) world.getDataManager()).getDirectory();
+        return world.getDataManager().getDirectory();
     }
 
     @Override