Fix description editor initially empty

[annplatoworld]

Fixes #26665

This is a regression introduced by previous changes most likely #26535, which moved description editing into a modal dialog. CodeMirror cannot compute its layout while its container is hidden (display: none on a <dialog> before showModal()), so the editor rendered empty until the window was resized and CodeMirror's resize handler kicked in.

Initial fix

Calling refresh() on each CodeMirror instance inside the dialog right after showModal() forces it to recalculate immediately.

Updated fix

Use setTimeout to delay behavior setup until after the dialog is shown, so CodeMirror can initialize with the correct dimensions. This avoids coupling the generic Dialog component to CodeMirror.
Thanks @timja for the suggestion.

Testing done

Manually reproduced and verified the fix in a local development instance

1. Created a freestyle job.
2. Set its description with the Safe HTML formatter and saved.
3. Refreshed the page and clicked "Edit description".

Before the change: the editor opened empty; content only appeared after resizing the window.
After the change: the editor opens with the existing description rendered correctly.

Screenshots

Before

After

Proposed changelog entries

• Fix description editor rendering empty when reopened inside a modal dialog.

Proposed changelog category

/label regression-fix,web-ui

Proposed upgrade guidelines

N/A

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  Desired reviewers

  @zbynek, @timja

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Maintainer checklist

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[Copilot]

Pull request overview

Fixes a web UI regression where CodeMirror-backed description editors render empty when first opened inside a <dialog> (hidden via display: none prior to showModal()), by forcing CodeMirror to recalculate its layout immediately after the dialog becomes visible.

Changes:

• After calling dialog.showModal(), finds CodeMirror-enhanced <textarea class="codemirror"> elements inside the dialog and calls codemirrorObject.refresh() on each instance.

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[Copilot]

Pull request overview

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