✅(jest) Make tests run concurrently

[dubzzz]

Description

They used to be running in a concurrent fashion in the past. But we stopped doing it due to a recent regression on the stability of our CI with Node 23.

The regression being still noticeable even without it and because of the cost of not doing the runs in a concurrent fashion, we move back to concurrent execution.

Checklist — Don't delete this checklist and make sure you do the following before opening the PR

• The name of my PR follows gitmoji specification
• My PR references one of several related issues (if any)
  • New features or breaking changes must come with an associated Issue or Discussion
  • My PR does not add any new dependency without an associated Issue or Discussion
• My PR includes bumps details, please run yarn bump and flag the impacts properly
• My PR adds relevant tests and they would have failed without my PR (when applicable)

Advanced

• Category: ✅ Add or update tests
• Impacts: Faster CI

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Latest commit: a10166a

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Latest deployment of this branch, based on commit a10166a:

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[github-actions]

👋 A preview of the new documentation is available at: http://671fde65e834e833a687328d--dubzzz-fast-check.netlify.app

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.27%. Comparing base (e0d1ced) to head (a10166a).
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5378   +/-   ##
=======================================
  Coverage   95.27%   95.27%           
=======================================
  Files         234      234           
  Lines       10478    10478           
  Branches     2795     2795           
=======================================
  Hits         9983     9983           
  Misses        495      495           

Flag	Coverage Δ
unit-tests	95.27% <ø> (ø)
unit-tests-18.x-Linux	95.27% <ø> (ø)
unit-tests-20.x-Linux	95.27% <ø> (ø)
unit-tests-22.x-Linux	95.27% <ø> (ø)
unit-tests-latest-Linux	95.27% <ø> (ø)

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[github-actions]

👋 A preview of the new documentation is available at: http://67209856809930aa0473794a--dubzzz-fast-check.netlify.app

[github-actions]

👋 A preview of the new documentation is available at: http://67209c5178a44c2e819e388b--dubzzz-fast-check.netlify.app

[github-actions]

👋 A preview of the new documentation is available at: http://67209ef0908ab6b570e4fdff--dubzzz-fast-check.netlify.app