fix: skip snow usage for MV3 test build

[weizman]

This MR introduced the problem, integrates Snow usage with LavaMoat to protect the application.

• Snow is a browser JS security solution, and therefore it expects the context it tries to defend to have a DOM.
• In MV3, we no longer have a background context with a DOM, but a service worker that is DOM-less.
• Therefore, use-snow.js file fails, because it expects window to exist, but in a service worker it doesn't.

The proposed fix is pretty simple, detect runtime execution env is a worker, and if so, skip using Snow.

[github-actions]

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[codecov]

Codecov Report

Merging #19827 (ad846ab) into develop (4846543) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop   #19827      +/-   ##
===========================================
- Coverage    69.72%   69.72%   -0.01%     
===========================================
  Files          982      982              
  Lines        37045    37045              
  Branches      9935     9935              
===========================================
- Hits         25828    25826       -2     
- Misses       11217    11219       +2     

see 2 files with indirect coverage changes