Add OCI manifest to allowed media types of docker manifest list

[gerrod3]

Assisted by: cursor-compose-2.5

📜 Checklist

• Commits are cleanly separated with meaningful messages (simple features and bug fixes should be squashed to one commit)
• A changelog entry or entries has been added for any significant changes
• Follows the Pulp policy on AI Usage
• (For new features) - User documentation and test coverage has been added

See: Pull Request Walkthrough

[patchback]

Backport to 2.20: 💚 backport PR created

✅ Backport PR branch: patchback/backports/2.20/e42c6efab7fd142e8376883324241a9a79dac1d8/pr-2369

Backported as #2371

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 2.26: 💚 backport PR created

✅ Backport PR branch: patchback/backports/2.26/e42c6efab7fd142e8376883324241a9a79dac1d8/pr-2369

Backported as #2372

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 2.27: 💚 backport PR created

✅ Backport PR branch: patchback/backports/2.27/e42c6efab7fd142e8376883324241a9a79dac1d8/pr-2369

Backported as #2375

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 2.24: 💚 backport PR created

✅ Backport PR branch: patchback/backports/2.24/e42c6efab7fd142e8376883324241a9a79dac1d8/pr-2369

Backported as #2373

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 2.22: 💚 backport PR created

✅ Backport PR branch: patchback/backports/2.22/e42c6efab7fd142e8376883324241a9a79dac1d8/pr-2369

Backported as #2376

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[patchback]

Backport to 2.28: 💚 backport PR created

✅ Backport PR branch: patchback/backports/2.28/e42c6efab7fd142e8376883324241a9a79dac1d8/pr-2369

Backported as #2374

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.