[JENKINS-69489] - Hide restart checkbox if the controller doesn't support it

[NotMyFault]

See JENKINS-69489.

I refactored the existing code a bit to use a Jenkins checkbox rather than labels and inputs and to display the checkbox only, if the controller can be restarted that way through the update center. Instead of displaying a label regardless, the if block above.

Testing done

Looks and works like that on macOS:

Testing on a Windows VM doesn't show the checkbox. As noted by James, Windows controllers don't support that:

Proposed changelog entries

• Hide 'Restart Jenkins' checkbox in the update center, if the controller doesn't support it.

Proposed upgrade guidelines

N/A

Submitter checklist

• The Jira issue, if it exists, is well-described.
• The changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developers, depending on the change) and are in the imperative mood (see examples).
  • Fill in the Proposed upgrade guidelines section only if there are breaking changes or changes that may require extra steps from users during upgrade.
• There is automated testing or an explanation as to why this change has no tests.
• New public classes, fields, and methods are annotated with @Restricted or have @since TODO Javadocs, as appropriate.
• New deprecations are annotated with @Deprecated(since = "TODO") or @Deprecated(forRemoval = true, since = "TODO"), if applicable.
• New or substantially changed JavaScript is not defined inline and does not call eval to ease future introduction of Content Security Policy (CSP) directives (see documentation).
• For dependency updates, there are links to external changelogs and, if possible, full differentials.
• For new APIs and extension points, there is a link to at least one consumer.

Desired reviewers

@mention

Maintainer checklist

Before the changes are marked as ready-for-merge:

• There are at least two (2) approvals for the pull request and no outstanding requests for change.
• Conversations in the pull request are over, or it is explicit that a reviewer is not blocking the change.
• Changelog entries in the pull request title and/or Proposed changelog entries are accurate, human-readable, and in the imperative mood.
• Proper changelog labels are set so that the changelog can be generated automatically.
• If the change needs additional upgrade steps from users, the upgrade-guide-needed label is set and there is a Proposed upgrade guidelines section in the pull request title (see example).
• If it would make sense to backport the change to LTS, a Jira issue must exist, be a Bug or Improvement, and be labeled as lts-candidate to be considered (see query).

[timja]

nice

[timja]

/label ready-for-merge

---

This PR is now ready for merge, after ~24 hours, we will merge it if there's no negative feedback.

Thanks!

[daniel-beck]

@NotMyFault Why did you (attempt to) make the checkbox here readonly? It doesn't work because 4cac031#diff-6fbee721e02514a54ede8e6e5ed37d3af538239842117a33b7ee905b0a518c81R6 is wrong. Asking because I want to fix my bug and want to ensure I'm not introducing a different one.

[NotMyFault]

Good question, actually. I think the attribute is obsolete and can be removed, given the if-condition represents the default state and the checkbox should work here.