[JENKINS-73838] Compatibility for Jenkins#doSafeRestart(StaplerRequest, String)

[basil]

See JENKINS-73838. Minor flaw in the EE 9 compatibility layer: Jenkins#doSafeRestart(StaplerRequest, String) was changed to StaplerRequest2 without providing a compatibility method, resulting in a proprietary plugin failing with:

java.lang.NoSuchMethodError: 'org.kohsuke.stapler.HttpResponse jenkins.model.Jenkins.doSafeRestart(org.kohsuke.stapler.StaplerRequest, java.lang.String)'

Fixed by providing the missing method.

Testing done

Verified that the call to Jenkins#doSafeRestart(StaplerRequest, String) could not be compiled with 2.478 but could be compiled after this PR.

Proposed changelog entries

Restore compatibility with plugins calling Jenkins#doSafeRestart(StaplerRequest, String).

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.
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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).
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8. For new APIs and extension points, there is a link to at least one consumer.

Desired reviewers

@mention

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

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[MarkEWaite]

Thanks!

[MarkEWaite]

This PR is now ready for merge. We will merge it after approximately 24 hours if there is no negative feedback.