Fix API teleport when Player is passenger

[Doc94]

This close #12737
currently the API with the passengers flags works for normal entities but when the passenger is a player this not works, the PR move that logic when need teleport and retain-passengers to use the NMS teleport like happen with crossDimension teleport and if not just use the snapTo

[Doc94]

An example running

this.getServer().getCommandMap().register("fallback", new BukkitCommand("test1", "cool hi command", "<>", List.of("hialias")) {
            @Override
            public boolean execute(@NotNull CommandSender sender, @NotNull String commandLabel, @NotNull String[] args) {
                if (sender instanceof Player player) {
                    Entity vehicle = player.getVehicle();
                    if (vehicle != null) {
                        vehicle.teleport(vehicle.getLocation().clone().add(0, 5, 0), TeleportFlag.EntityState.RETAIN_VEHICLE, TeleportFlag.EntityState.RETAIN_PASSENGERS);

                    }
                }
                return true;
            }
        });

2025-06-25_11-21-14.mp4

[Clexus]

I want to mention that the retain_vehicle flag also doesn't work for non-player entities