Allow teleporting through end gateways as a passenger/vehicle

Vanilla allows this now for same world teleports

Fixes #3735

Spigot-Server-Patches/Ensure-safe-gateway-teleport.patch

@@ -17,7 +17,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 -                this.a((Entity) list.get(this.world.random.nextInt(list.size())));
 +            // Paper start
 +            for (Entity entity : list) {
-+                if (!entity.isPassenger() && !entity.isVehicle() && entity.canPortal()) {
++                if (entity.canPortal()) {
 +                    this.a(entity);
 +                    break;
 +                }