chore: Update sonatype endpoint for publishing

[vincetran]

• PR title and description conform to Pull Request guidelines.

Issue #, if available: N/A

Description of changes:
Followed the migration wiki and Central Portal documentation to make these changes. After this is pushed, I'll have to also modify the build spec for the publish CodeBuild project as we need to manually tell the API "we're done uploading, start staging the repository" then we can finish our publishing flow from the UI.

How did you test these changes?
Did test publishes of Amplify Android to Central Portal and validated that they showed up.

Documentation update required?

• No
• Yes (Please include a PR link for the documentation update)

General Checklist

• Added Unit Tests
• Added Integration Tests
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Ensure commit message has the appropriate scope (e.g fix(storage): message, feat(auth): message, chore(all): message)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 42.08%. Comparing base (038707a) to head (92b264e).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3071      +/-   ##
==========================================
+ Coverage   42.06%   42.08%   +0.01%     
==========================================
  Files         992      992              
  Lines       31544    31544              
  Branches     4648     4648              
==========================================
+ Hits        13270    13274       +4     
+ Misses      16813    16808       -5     
- Partials     1461     1462       +1     

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