fix: skip to delete scan reports if the digest still referenced

[chlins]

Avoid to delete the scan reports in case the artifact deleted but still referenced by the other artifacts.

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Comprehensive Summary of your change

Issue being fixed

Fixes #19105

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• Well Written Title and Summary of the PR
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[codecov]

Codecov Report

Merging #19110 (9d84836) into main (403b616) will decrease coverage by 22.56%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             main   #19110       +/-   ##
===========================================
- Coverage   67.40%   44.84%   -22.56%     
===========================================
  Files         992      244      -748     
  Lines      108770    13405    -95365     
  Branches     2751     2751               
===========================================
- Hits        73315     6012    -67303     
+ Misses      31517     7087    -24430     
+ Partials     3938      306     -3632     

Flag	Coverage Δ
unittests	44.84% <ø> (-22.56%)	⬇️

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see 752 files with indirect coverage changes

[wy65701436]

lgtm