raiding mechanic world border sand stacking

currently tnt and sand interact with the world border as if its a solid object. this causes issues for players that build on the world border as it allows raiders to more easily bypass your defenses. I suggest making it so that any tnt or sand (gravity block) that has forward momentum in the direction of the world border and then interacts with it despawns. this issue is similar to allowing tnt and sand to exist over the max y height