Remove hint from batch sample

When https://github.com/spring-projects/spring-batch/issues/4248 is resolved remove the following hint to the batch-job sample from this commit : https://github.com/spring-cloud/spring-cloud-task/commit/741977ee7f0316f703147773e25445da8e6006b4