Fix job/step configuration when no name is provided

Resolves #5027

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/step/AbstractStep.java

@@ -94,7 +94,6 @@ public AbstractStep() {
 	 */
 	@Deprecated(since = "6.0", forRemoval = true)
 	public AbstractStep(String name) {
-		Assert.notNull(name, "Step name must not be null");
 		this.name = name;
 	}
 

spring-batch-samples/src/main/java/org/springframework/batch/samples/helloworld/HelloWorldJobConfiguration.java

@@ -31,15 +31,15 @@ public class HelloWorldJobConfiguration {
 
 	@Bean
 	public Step step(JobRepository jobRepository) {
-		return new StepBuilder("step", jobRepository).tasklet((contribution, chunkContext) -> {
+		return new StepBuilder(jobRepository).tasklet((contribution, chunkContext) -> {
 			System.out.println("Hello world!");
 			return RepeatStatus.FINISHED;
 		}).build();
 	}
 
 	@Bean
 	public Job job(JobRepository jobRepository, Step step) {
-		return new JobBuilder("job", jobRepository).start(step).build();
+		return new JobBuilder(jobRepository).start(step).build();
 	}
 
 }