ci: fix public logs link

[dbolduc]

Mirror the logsBucket path:

https://github.com/dbolduc/google-cloud-cpp/blob/2519bb74bfb849be1df98152d55f750ed195013a/ci/cloudbuild/cloudbuild.yaml#L68

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This change is 

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.58%. Comparing base (bdecef6) to head (2519bb7).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14418      +/-   ##
==========================================
- Coverage   93.58%   93.58%   -0.01%     
==========================================
  Files        2313     2313              
  Lines      206884   206884              
==========================================
- Hits       193617   193615       -2     
- Misses      13267    13269       +2     

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