prevent duplication of Prometheus attributes

[mariomac]

Checklist

• If this enhances / fixes / changes a core feature, I have updated the features documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 43.77%. Comparing base (0f2b983) to head (a1baa2e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1355      +/-   ##
==========================================
- Coverage   43.79%   43.77%   -0.03%     
==========================================
  Files         308      308              
  Lines       33495    33495              
==========================================
- Hits        14669    14661       -8     
- Misses      17885    17893       +8     
  Partials      941      941              

Flag	Coverage Δ
integration-test	22.03% <100.00%> (+0.32%)	⬆️
integration-test-arm	0.00% <0.00%> (ø)
integration-test-vm-x86_64-5.15.152	?
integration-test-vm-x86_64-6.10.6	?
k8s-integration-test	2.33% <0.00%> (ø)
oats-test	0.00% <0.00%> (ø)
unittests	44.60% <100.00%> (-0.02%)	⬇️

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