samples: reduce dependencies to docker hub

[manuelh-dev]

Merge Checklist

• Followed patch format from upstream recommendation: https://github.com/kata-containers/community/blob/main/CONTRIBUTING.md#patch-format
  • Included a single commit in a given PR - at least unless there are related commits and each makes sense as a change on its own.
• Aware about the PR to be merged using "create a merge commit" rather than "squash and merge" (or similar)
• genPolicy only: Ensured the tool still builds on Windows
• The upstream/missing label (or upstream/not-needed) has been set on the PR.

Summary

Use container image sources from ACR/MCR.

Test Methodology

• Internal test pipelines
• validated that with mcr.microsoft.com/mirror/docker/library/ubuntu:jammy the policy hash changes if compiled without || layer.media_type.eq(manifest::IMAGE_LAYER_GZIP_MEDIA_TYPE)