fix(accordion): use realistic example content in stories, add ADR

[tay1orjones]

Closes #21190

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.03%. Comparing base (c946164) to head (ca96e14).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #21561      +/-   ##
==========================================
- Coverage   87.04%   87.03%   -0.01%     
==========================================
  Files         539      539              
  Lines       43521    43521              
  Branches     6737     6702      -35     
==========================================
- Hits        37881    37880       -1     
- Misses       5477     5478       +1     
  Partials      163      163              

Flag	Coverage Δ
main-packages	86.19% <ø> (ø)
web-components	87.48% <ø> (-0.01%)	⬇️

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