fix: monospace font family for one-theme

[mxschll]

Description

Defines monospace font for One Theme and makes code editor use that definition.

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 97.61%. Comparing base (ee8f660) to head (5f41503).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4827   +/-   ##
=======================================
  Coverage   97.61%   97.61%           
=======================================
  Files         952      952           
  Lines       30816    30816           
  Branches    11317    11318    +1     
=======================================
  Hits        30081    30081           
+ Misses        728      688   -40     
- Partials        7       47   +40     

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[NathanZlion]

LGTM