Convert SortableElements into a custom element

[tvdeyen]

That way we do not need to initialize them
ourselves, but can let the Browser handle it.

Checklist

• I have followed Pull Request guidelines
• I have added a detailed description into each commit message
• I have added tests to cover this change

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.35%. Comparing base (e01d6d8) to head (bcb1590).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3560   +/-   ##
=======================================
  Coverage   97.35%   97.35%           
=======================================
  Files         308      308           
  Lines        8025     8025           
=======================================
  Hits         7813     7813           
  Misses        212      212           

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