chore: Refactor card margin to its parent

[jperals]

Description

Move the spacing between the cards, from within the interior of each card to within the li element that wraps it.

This is a small preparation for the component decomposition (related: #4084)

How has this been tested?

Ran in my pipeline.

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.16%. Comparing base (6a5486b) to head (e43c1e4).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4208   +/-   ##
=======================================
  Coverage   97.16%   97.16%           
=======================================
  Files         879      879           
  Lines       25780    25780           
  Branches     9328     9328           
=======================================
  Hits        25049    25049           
  Misses        725      725           
  Partials        6        6           

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