Convert the string "0" to number 0

[AllForNothing]

1. Fixes Retention Policy Not Working When Configured via Harbor User Interface #19046
   Convert the string "0" to the number 0 for the tag retention rules
   Thank you for contributing to Harbor!

Comprehensive Summary of your change

Issue being fixed

Fixes #(issue)

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• 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"
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[codecov]

Codecov Report

Merging #19080 (7937cf1) into main (d347752) will decrease coverage by 0.02%.
The diff coverage is 0.00%.

❗ Current head 7937cf1 differs from pull request most recent head be7a3f6. Consider uploading reports for the commit be7a3f6 to get more accurate results

@@            Coverage Diff             @@
##             main   #19080      +/-   ##
==========================================
- Coverage   67.40%   67.38%   -0.02%     
==========================================
  Files         992      992              
  Lines      108752   108754       +2     
  Branches     2750     2751       +1     
==========================================
- Hits        73300    73289      -11     
- Misses      31519    31532      +13     
  Partials     3933     3933              

Flag	Coverage Δ
unittests	67.38% <0.00%> (-0.02%)	⬇️

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Files Changed	Coverage Δ
...ation/tag-retention/add-rule/add-rule.component.ts	22.22% <0.00%> (-0.39%)	⬇️

... and 9 files with indirect coverage changes