update ECR adapter to allow for ecr-public to be mirored

[goshlanguage]

Thank you for contributing to Harbor!

Comprehensive Summary of your change

Allows ecr-public to be mirrored in the same way ecr-fips can be today

Issue being fixed

Fixes #(issue)
#22346

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.

[chlins]

@vincentni Please help to take a look for this change, thanks!

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.88%. Comparing base (c8c11b4) to head (f0b8e52).
⚠️ Report is 568 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main   #22351       +/-   ##
===========================================
+ Coverage   45.36%   65.88%   +20.51%     
===========================================
  Files         244     1072      +828     
  Lines       13333   115932   +102599     
  Branches     2719     2927      +208     
===========================================
+ Hits         6049    76386    +70337     
- Misses       6983    35310    +28327     
- Partials      301     4236     +3935     

Flag	Coverage Δ
unittests	65.88% <ø> (+20.51%)	⬆️

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

Files with missing lines	Coverage Δ
src/pkg/reg/adapter/awsecr/adapter.go	68.62% <ø> (ø)

... and 985 files with indirect coverage changes

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[goshlanguage]

@chlins I don't mean to nag, but is it possible we won't get a review from @vincentni? Their github history looks a little sparse, and its been a few weeks.

If there are other tests I can add to raise confidence here, I'm happy to do so. Please let me know.

Thanks!