fix: Fixed the verify_dockerhub and verify_public_ecr functions to use the correct reference tag when verifying BUILD_VERSION=3 releases.

[mye956]

Summary

For BUILD_VERSION=3, the pipeline publishes a :3 major version tag instead of :latest. However, the verification functions were always comparing against :latest, then doing a separate optional check against :3. This meant:

1. For BUILD_VERSION=3, comparing against :latest is wrong — that tag points to the BUILD_VERSION=2 image.
2. The :3 tag check was guarded by check_tag_exists, making it a soft/optional verification rather than a hard requirement.

This change will restructure both functions so the reference tag is selected based on BUILD_VERSION:

• BUILD_VERSION=3 → verifies against :3 and :init-3
• All others → verifies against :latest and :init-latest

The check_tag_exists guard was also removed, meaning the :3 tag is now expected to exist when verifying a BUILD_VERSION=3 release.

Issue #, if available:

Testing

Manually tested via a separate bash script with the same logic

make debug succeeded:
Integ tests succeeded:
New tests cover the changes:

Description for the changelog

fix: Fixed the verify_dockerhub and verify_public_ecr functions to use the correct reference tag when verifying BUILD_VERSION=3 releases.

Licensing

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