Empty ui-grid-cell in Js Dialog

[banobepascal]

Potential mentors: @eszkadev @Darshan-upadhyay1110

Steps to reproduce

1. Open a Writer/Calc document in Collabora Online.
2. Go to Format and click on Page Style/Format Page
3. A Page style dialog is opened

Obervation: While rendering the Page Style dialog, an empty <div class='ui-grid-cell'></div> is generated, which introduces unnecessary spacing and causes content misalignment

Expected Behavior

No empty grid cell should be rendered unless it serves a structural purpose. The layout should remain clean and aligned without unintended gaps

Code pointers

https://github.com/CollaboraOnline/online/blob/b9d7d4728cb57faff52fa3729726cf5c0651ce65/browser/src/control/jsdialog/Widget.Containers.ts#L102