chore: Imports STSN utils from toolkit

[pan-kot]

Description

Importing STSN utils from the toolkit.

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 97.10%. Comparing base (2212c21) to head (88d78d3).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3808      +/-   ##
==========================================
- Coverage   97.10%   97.10%   -0.01%     
==========================================
  Files         840      839       -1     
  Lines       24472    24418      -54     
  Branches     8637     8621      -16     
==========================================
- Hits        23763    23710      -53     
- Misses        659      701      +42     
+ Partials       50        7      -43     

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[gethinwebster]

looks great!