Update the parameter to search cosign

[AllForNothing]

1.Fixes #18960

Thank you for contributing to Harbor!

Comprehensive Summary of your change

Issue being fixed

Fixes #(issue)

Please indicate you've done the following:

• Well Written Title and Summary of the PR
• Label the PR as needed. "release-note/ignore-for-release, release-note/new-feature, release-note/update, release-note/enhancement, release-note/community, release-note/breaking-change, release-note/docs, release-note/infra, release-note/deprecation"
• Accepted the DCO. Commits without the DCO will delay acceptance.
• Made sure tests are passing and test coverage is added if needed.
• Considered the docs impact and opened a new docs issue or PR with docs changes if needed in website repository.

[codecov]

Codecov Report

Merging #18963 (e476825) into main (9091661) will increase coverage by 22.49%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             main   #18963       +/-   ##
===========================================
+ Coverage   44.91%   67.40%   +22.49%     
===========================================
  Files         244      993      +749     
  Lines       13389   108772    +95383     
  Branches     2747     2747               
===========================================
+ Hits         6013    73321    +67308     
- Misses       7072    31514    +24442     
- Partials      304     3937     +3633     

Flag	Coverage Δ
unittests	67.40% <ø> (+22.49%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...t/artifact-list-tab/artifact-list-tab.component.ts	42.37% <ø> (-0.45%)	⬇️

... and 752 files with indirect coverage changes

[wy65701436]

lgtm