revert: Update custom dev pages to use light-dark method (#3896)

[georgylobko]

This reverts commit 4c80008.

Description

Related links, issue #, if available: n/a

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 97.17%. Comparing base (7d5b327) to head (48f01fb).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3963   +/-   ##
=======================================
  Coverage   97.17%   97.17%           
=======================================
  Files         854      854           
  Lines       24993    24993           
  Branches     8806     8805    -1     
=======================================
  Hits        24287    24287           
- Misses        658      700   +42     
+ Partials       48        6   -42     

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