This reverts commit d1d3f4d, restoring the registry login to
`-u ${{ github.actor }}` and dropping the accompanying comment.
Reverted at the request of the issue owner on FMG-5. The release job is
therefore back to the state described in that issue: a tag pushed by
butterrobot logs in as butterrobot, and the image push is expected to fail
with `401 Unauthorized: reqPackageAccess`.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>