feat: Make action card design token public + themeable

[SpyZzey]

Description

This PR exposes the action card design tokens by making them public and themeable. This includes:

• borderWidthActionCardActive
• borderWidthActionCardDefault
• borderWidthActionCardDisabled
• borderWidthActionCardHover
• colorBackgroundActionCardActive
• colorBackgroundActionCardDefault
• colorBackgroundActionCardDisabled
• colorBackgroundActionCardHover
• colorBorderActionCardActive
• colorBorderActionCardDefault
• colorBorderActionCardDisabled
• colorBorderActionCardHover
• colorTextActionCardDisabled
• spaceActionCardHorizontalDefault
• spaceActionCardHorizontalEmbedded
• spaceActionCardVerticalDefault
• spaceActionCardVerticalEmbedded

Related links, issue #, if available: n/a

How has this been tested?

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?

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.42%. Comparing base (ebb4068) to head (7535011).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4505   +/-   ##
=======================================
  Coverage   97.42%   97.42%           
=======================================
  Files         936      936           
  Lines       29616    29616           
  Branches    10760    10761    +1     
=======================================
  Hits        28852    28852           
+ Misses        757      716   -41     
- Partials        7       48   +41     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.