[JENKINS-71726] [JENKINS-71727] remove inline javascript

[mawinter69]

See JENKINS-71727.
See JENKINS-71726.

Testing done

JENKINS-71727:

• Do not log in
• visit a page that is restricted
• you get redirected to the login page
• login
• get redirected to the original page
• run curl -u http://jenkins/job/test/ and checked output contains data-redirect-url to loginform and javascript src points to proper script url.
• Message Authentication required is included in the output

JENKINS-71726:

• Create a job without parameters
• run it once
• change job to require parameters
• run job with parameters
• visit job/2/parameters
• click on Previous Build
• you get redirected to job/1/
• run curl -u user:token http://jenkins/job/test/1/parameters/ and checked output contains data-redirect-url and javascript src points to proper script url.
• Proper message Not found is included in the output

Proposed changelog entries

N/A

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

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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.
3. Changelog entries in the pull request title and/or Proposed changelog entries are accurate, human-readable, and in the imperative mood.
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).
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[Kevin-CB]

Thanks for this PR @mawinter69, I'll try to review it as soon as possible.

[Kevin-CB]

From a security perspective, this is fine. However, I've noticed some latency during each redirection, which, if I'm correct, wasn't present previously.

For example, when I try to access my job without being authenticated, it doesn't redirect me to the login form instantly but displays a blank page for longer than usual.

I think, the timing difference is related to the time it takes to load the redirect.js script and execute it.

Perhaps we could choose a different CSP approval approach, using nonce or hash.

[Kevin-CB]

I investigated further as to why I was experiencing this delay, and found that it was simply because the script wasn't being executed. The delay I was encountering was due to the redirection initiated by the meta refresh tag, which has a delay set to 1 second (content='1).

Upon closer look on what happened, the rendered page was:

The script tag is malformed, taking the remainder of our request.
I'm not sure why, but the self-closing tag isn't functioning correctly. Closing it with a full tag resolves this issue.

[Kevin-CB]

I retested it with your change, and it works fine.

[MarkEWaite]

I've tested with this change applied to the master branch and it works well in my testing also.

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

/label ready-for-merge