[JENKINS-68904] Adress ESLint violations

[NotMyFault]

Addresses the ESLint part of JENKINS-68904
The latest commit simulates a CI failure and will be reverted once demonstrated.

Proposed changelog entries

• Entry 1: Issue, Human-readable Text
• ...

Proposed upgrade guidelines

N/A

Submitter checklist

• (If applicable) Jira issue is well described
• Changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developer, depending on the change) and are in the imperative mood. Examples
  • Fill-in the Proposed changelog entries section only if there are breaking changes or other changes which may require extra steps from users during the upgrade
• Appropriate autotests or explanation to why this change has no tests
• New public classes, fields, and methods are annotated with @Restricted or have @since TODO Javadoc, as appropriate.
• New deprecations are annotated with @Deprecated(since = "TODO") or @Deprecated(forRemoval = true, since = "TODO") if applicable.
• For dependency updates: links to external changelogs and, if possible, full diffs

Desired reviewers

@mention

Maintainer checklist

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

• There are at least 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 does not block the change
• Changelog entries in the PR 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, upgrade-guide-needed label is set and there is a Proposed upgrade guidelines section in the PR title. (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).

[NotMyFault]

The failure can be seen on https://ci.jenkins.io/job/Core/job/jenkins/job/PR-6794/2/consoleFull and has been reverted by now.

[basil]

commit 6b70fc8 is not fully reverted by commit f40fca8. I would prefer that it be fully reverted and that we discuss the topic of enforcement in a separate PR (the fix for JENKINS-68903), since there are multiple ways to implement JENKINS-68903 and the partial revert in f40fca8 implements the solution to JENKINS-68903 that I describe in that bug as "less attractive."

[basil]

Ah yes, the intricacies of variable scope in JavaScript… 😄 I don't understand this but I trust you.

[basil]

Ah yes, the intricacies of variable scope in JavaScript… 😄 I don't understand this but I trust you.

[NotMyFault]

The commit has been reverted properly 👍🏻

[basil]

This PR is now ready for merge. We will merge it after approximately 24 hours if there is no negative feedback. Please see the merge process documentation for more information about the merge process. Thanks!