fix: resolve wcag2aa color contrast issues

[jonas-jonas]

Also enables a11y testing on the storybook stories.

Related Issue or Design Document

Checklist

• I have read the contributing guidelines and signed the CLA.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I have read the security policy.
• I confirm that this pull request does not address a security vulnerability.
  If this pull request addresses a security vulnerability,
  I confirm that I got approval (please contact [email protected]) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation within the code base (if appropriate).

Further comments

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 50.59%. Comparing base (f3fad4d) to head (d2c4010).
Report is 40 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #367      +/-   ##
==========================================
+ Coverage   42.43%   50.59%   +8.16%     
==========================================
  Files         136      139       +3     
  Lines        2008     2113     +105     
  Branches      288      314      +26     
==========================================
+ Hits          852     1069     +217     
+ Misses       1149     1032     -117     
- Partials        7       12       +5     

Components	Coverage Δ
@ory/elements-react	47.37% <42.20%> (+10.58%)	⬆️
@ory/nextjs	64.33% <74.24%> (-1.65%)	⬇️