chore(repo-server): unify semver resolution in new versions subpackage (#20216)

[rouke-broersma]

Cherry-picked chore(repo-server): unify semver resolution in new versions subpackage (#20216)

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• The title of the PR conforms to the Toolchain Guide
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).
• My new feature complies with the feature status guidelines.
• I have added a brief description of why this PR is necessary and/or what this PR solves.
• Optional. My organization is added to USERS.md.
• Optional. For bug fixes, I've indicated what older releases this fix should be cherry-picked into (this may or may not happen depending on risk/complexity).

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 55.97%. Comparing base (59d4519) to head (7c3df73).
⚠️ Report is 42 commits behind head on release-3.0.

Files with missing lines	Patch %	Lines
util/helm/index.go	0.00%	6 Missing ⚠️
reposerver/repository/repository.go	80.95%	3 Missing and 1 partial ⚠️
util/versions/tags.go	92.10%	2 Missing and 1 partial ⚠️
util/helm/client.go	88.88%	1 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           release-3.0   #23310      +/-   ##
===============================================
+ Coverage        55.91%   55.97%   +0.06%     
===============================================
  Files              343      343              
  Lines            57435    57405      -30     
===============================================
+ Hits             32114    32132      +18     
+ Misses           22667    22633      -34     
+ Partials          2654     2640      -14     

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