Add ability to provide a label to a jf command

### Is your feature request related to a problem? Please describe.

Currently you add a jf command as a step like this:

```groovy
jf "release-bundle-delete-local --project proj --server-id artifactory --quiet some-bundle 1.0.0"
```

When looking at this step in Jenkins BlueOcean it looks like this:

_release-bundle-delete-local --project proj --server-id artifactory --quiet some-bundle 1.0.0_ **— jf command**

The request is to add the ability to provide a label to the step in the same way we do for sh or bat

### Describe the solution you'd like to see

Add the ability to write the command above like this:
```groovy
jf label: 'Delete the release bundle',
script: "release-bundle-delete-local --project proj --server-id artifactory --quiet some-bundle 1.0.0"
```

resulting in the step looking like this:

_release-bundle-delete-local --project proj --server-id artifactory --quiet some-bundle 1.0.0_ **— Delete the release bundle**

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Locate the implementation of the jf pipeline step and compare it with the existing sh or bat steps' label handling. Verify the requested label and script syntax, and confirm that Jenkins BlueOcean displays the supplied label instead of the default jf command text.

Written by the indexing model from the issue text.