Remove /exception endpoint

[daniel-beck]

I agree with the author of the test I'm changing: This endpoint shouldn't exist in production code.

Given the reference to JENKINS-13625 in 18963ee it apparently was always only intended as a test utility, which can be done more nicely as a @TestExtension in tests.

Testing done

None, too trivial.

Quick GH code finds no callers.

Proposed changelog entries

None, too minor.

Proposed changelog category

/label skip-changelog

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.
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• 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

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

Maintainer checklist

• 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).

[MarkEWaite]

Thanks! I confirmed with interactive testing that the /exception endpoint is no longer available with this pull request and that in previous releases it generated an exception

2025-02-24 16:48:52.852+0000 [id=366419]        WARNING h.i.i.InstallUncaughtExceptionHandler#handleException: Caught unhandled exception with ID aaf95b8c-7aba-4eaf-9c28-986c495abc95
java.lang.RuntimeException
        at jenkins.model.Jenkins.doException(Jenkins.java:4473)
        at java.base/java.lang.invoke.MethodHandle.invokeWithArguments(Unknown Source)
        at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:484)
        at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:497)
        at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:218)
        at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:140)
        at org.kohsuke.stapler.MetaClass$12.doDispatch(MetaClass.java:686)
        at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:61)
        at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:800)