run/logging-manual: clarify Artifact Registry setup for deployment #14633

The Deploy section in run/logging-manual/README.md uses gcr.io image URLs without explaining the required Artifact Registry setup.

Container Registry no longer accepts image writes. Artifact Registry-backed gcr.io URLs remain supported, but the README does not explain that prerequisite.

Suggested change: use a REGION-docker.pkg.dev image URL in both build and deploy commands, and link instructions for creating the Docker repository and configuring build permissions. Alternatively, keep gcr.io and link its Artifact Registry setup requirements.

This is based on reviewing the README and official documentation; I have not reproduced a deployment failure.