Update design list item component to use GitLab UI classes

What does this MR do?

This MR updates legacy utility classes for design list item component to GitLab UI utility classes when it's possible

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Issue: #219730 (closed)