chore: Experiment with css theme generation

[pan-kot]

Description

Depends on: cloudscape-design/theming-core#159

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?

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.39%. Comparing base (3025360) to head (c3e26ea).

Files with missing lines	Patch %	Lines
src/theming/index.ts	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4416      +/-   ##
==========================================
- Coverage   97.40%   97.39%   -0.01%     
==========================================
  Files         933      933              
  Lines       29486    29488       +2     
  Branches    10697    10697              
==========================================
  Hits        28720    28720              
- Misses        759      761       +2     
  Partials        7        7              

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