Add job name tag to spring.batch.job.active metric

[fmbenhassine]

As of v4.2, Spring Batch provides a micrometer metric called spring.batch.job.active of type LongTaskTimer that gives the number of active jobs. However, it is impossible to know which jobs are active because this metric is not tagged with the job name.

Tagging this metric with the job name would make it possible to know which jobs are active.