chore: Remove legacy markdown for Avatar Style API

[teodoranemes]

Description

This PR removes the legacy markdown for the Avatar Style API that was replaced by documenter automation.

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

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.17%. Comparing base (d555ae4) to head (1d59be1).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #86   +/-   ##
=======================================
  Coverage   96.17%   96.17%           
=======================================
  Files          29       29           
  Lines         679      679           
  Branches      114      114           
=======================================
  Hits          653      653           
  Misses         26       26           

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