[JENKINS-73297] Improve error handling when commit is not found

[uhafner]

See JENKINS-73297.

[github-actions]

☀️   Quality Monitor

   🚦   Tests: 100 % successful (✔️ 121 passed)
   〰️   Line Coverage: 87% (104 missed lines)
   ➰   Branch Coverage: 78% (53 missed branches)
     Mutation Coverage: 14% (368 survived mutations)
     CheckStyle: No warnings
     PMD: No warnings
     SpotBugs: No warnings

Created by Quality Monitor v1.9.0 (#00b9b1a). More details are shown in the GitHub Checks Result.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.11%. Comparing base (57957eb) to head (beeb13f).
Report is 13 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #815      +/-   ##
============================================
+ Coverage     83.60%   84.11%   +0.51%     
+ Complexity      207      206       -1     
============================================
  Files            25       25              
  Lines           805      806       +1     
  Branches         83       83              
============================================
+ Hits            673      678       +5     
+ Misses          101       96       -5     
- Partials         31       32       +1     

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[github-actions]

☀️   Quality Monitor

   🚦   Tests: 100 % successful (✔️ 121 passed)
   〰️   Line Coverage: 87% (104 missed lines)
   ➰   Branch Coverage: 78% (53 missed branches)
     Mutation Coverage: 14% (368 survived mutations)
     CheckStyle: No warnings
     PMD: No warnings
     SpotBugs: No warnings

Created by Quality Monitor v1.9.0 (#00b9b1a). More details are shown in the GitHub Checks Result.