[JENKINS-73246] Fix text shown in unexpected locale

[BobDu]

See JENKINS-73246.

Ref: #8912 (comment)

Special treatment if language is en

Testing done

run

mvn clean verify

Interactive test before this change shows Italian help text for "Manage Jenkins" -> "System" -> "Quiet period" when I am running in English language. After this change the help text for "Manage Jenkins" -> "System" -> "Quiet period" is correctly displayed as English.

Proposed changelog entries

• Show help text in the correct locale even if user has an alternate language option defined in their browser (regression in 2.444).

Proposed upgrade guidelines

N/A

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1. The Jira issue, if it exists, is well-described.
2. 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.
3. There is automated testing or an explanation as to why this change has no tests.
4. New public classes, fields, and methods are annotated with @Restricted or have @since TODO Javadocs, as appropriate.
5. New deprecations are annotated with @Deprecated(since = "TODO") or @Deprecated(forRemoval = true, since = "TODO"), if applicable.
6. 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).
7. For dependency updates, there are links to external changelogs and, if possible, full differentials.
8. For new APIs and extension points, there is a link to at least one consumer.

Desired reviewers

N/A

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

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2. Conversations in the pull request are over, or it is explicit that a reviewer is not blocking the change.
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4. Proper changelog labels are set so that the changelog can be generated automatically.
5. 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).
6. 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]

/label ready-for-merge

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

Thanks!

[MarkEWaite]

I'm accelerating the merge of this one because it would be nice to include in 2.452.3 as a backport.