Fix CI usage of secrets

[adriansmares]

Summary

References github/docs#6861
References #6154 (comment)

Apparently secrets are not available as part of if, so we need to inject the secret (which is not really secret, the region is not that special) as an environment variable and compare that.

Changes

• Inject the AWS_REGION as an environment variable, and then use it for the comparison.

Testing

CI.

Regressions

This fixes a regression in itself.

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.