[JENKINS-59684] Support "alert-info" for admin monitor in popup

[Wadeck]

• Add support for alert-info and alert-danger also in the popup for admin monitor.
• Also support the p tags in the message, discovered with the CSRF monitor message being only "half-styled".

Screenshots

Full page mode (ok before and after)

Popup mode

Before

After

For CSRF monitor, the paragraphs are now also correctly styled

Before

After

For security warnings

Before

After

See JENKINS-59684.

Proposed changelog entries

• Administrative monitors providing information message are now correctly styled in the popup mode

Submitter checklist

• JIRA issue is well described
• Changelog entry appropriate for the audience affected by the change (users or developer, depending on the change). Examples
  * Use the Internal: prefix if the change has no user-visible impact (API, test frameworks, etc.)
• [n/a] Appropriate autotests or explanation to why this change has no tests
• [n/a] For dependency updates: links to external changelogs and, if possible, full diffs

Desired reviewers

@recena @daniel-beck

[jvz]

Thanks for fixing this!

[daniel-beck]

Why does this edit style.css when #2857 worked on bootstrap.css etc.?

[Wadeck]

The alert-warning that was applied before comes from #1847.

The bootstrap.css is applied only to manage.jelly, don't ask me why. https://github.com/Wadeck/jenkins/blob/4d65572c6db9099ebcf8d2222159c069996670f9/core/src/main/resources/jenkins/model/Jenkins/manage.jelly#L33 and #2857

[oleg-nenashev]

💯 , thanks!
I was thinking about delivering upgrade guide heads-up through update centers, and this is a great foundation improvement for it

I plan to merge it tomorrow if no negative feedback