Fix WallMakeMask for regions not overriding contains(x, z) (#3349)

Author: SirYwell

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/mask/WallMakeMask.java

@@ -15,11 +15,12 @@ public WallMakeMask(Region region) {
     @Override
     public boolean test(BlockVector3 position) {
         int x = position.x();
+        int y = position.y();
         int z = position.z();
-        return !region.contains(x, z + 1) || !region.contains(x, z - 1) || !region.contains(x + 1, z) || !region.contains(
-                x - 1,
-                z
-        );
+        return !region.contains(x, y, z + 1) ||
+                !region.contains(x, y, z - 1) ||
+                !region.contains(x + 1, y, z) ||
+                !region.contains(x - 1, y, z);
     }
 
     @Override