Onboarding: Fix Git initialization problem

[ghengeveld]

Moved the Git prerequisite check before the project setup step because project setup requires Git to generate the Chromatic config file. Tweaked the Git setup message to be a bit more elegant and actionable.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 23 lines in your changes missing coverage. Please review.

Project coverage is 6.00%. Comparing base (cdec3a9) to head (fdbe074).
Report is 41 commits behind head on next.

Files with missing lines	Patch %	Lines
src/screens/Errors/GitNotFound.tsx	0.00%	13 Missing ⚠️
src/components/Box.tsx	0.00%	5 Missing ⚠️
src/Panel.tsx	0.00%	4 Missing ⚠️
src/preset.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            next    #371   +/-   ##
=====================================
  Coverage   6.00%   6.00%           
=====================================
  Files        169     169           
  Lines      14282   14289    +7     
  Branches     302     302           
=====================================
+ Hits         857     858    +1     
- Misses     13343   13350    +7     
+ Partials      82      81    -1     

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[ghengeveld]

🚀 PR was released in v4.0.0 🚀