chore(ui): fix carousel buttons not showing up on Firefox

[jahow]

The buttons are positioned absolutely and the component host is positioned relatively; without a "display: block" setting as well, the buttons were simply not showing up on Firefox.

Conclusion: do not position relatively something that isn't a block.

[github-actions]

Affected libs: ui-layout, feature-catalog, feature-record, feature-router, feature-dataviz, feature-editor, feature-search, feature-map, ui-elements, feature-notifications, ui-catalog, ui-search,
Affected apps: metadata-editor, datahub, demo, webcomponents, map-viewer, search, datafeeder,

• 🚀 Build and deploy storybook and demo on GitHub Pages
• 📦 Build and push affected docker images

[coveralls]

coverage: 84.424% (+0.6%) from 83.874%
when pulling a1996dc on fix-carousel-buttons
into 22f4da7 on main.

[github-actions]

📷 Screenshots are here!