Use github-script to get ref and sha instead of shell

[Frawless]

Type of change

• Refactoring

Description

Migrate determine-ref to use github-script instead of bash to properly get sha reference of commit used for PR STs verification.

Checklist

• Make sure all tests pass

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.67%. Comparing base (66ccc4e) to head (aab2c0b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #11975      +/-   ##
============================================
+ Coverage     74.66%   74.67%   +0.01%     
- Complexity     6399     6400       +1     
============================================
  Files           342      342              
  Lines         24228    24228              
  Branches       3190     3190              
============================================
+ Hits          18090    18093       +3     
+ Misses         4866     4865       -1     
+ Partials       1272     1270       -2     

see 1 file with indirect coverage changes

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