auto-docs: Update property docs for tag v26.1.8

[vbotbuildovich]

This PR auto-generates updated Redpanda property documentation for v26.1.8.

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📝 Walkthrough

Walkthrough

This PR updates documentation and configuration metadata for Redpanda version 26.1.8, advancing fallback version references in antora.yml from 26.1.6 to 26.1.8. It introduces two new cluster-level configuration properties: iceberg_rest_catalog_credentials_host (for Iceberg REST catalog credentials) and oidc_http_proxy_url (for OIDC proxy configuration). These properties are added to the property override definitions, JSON schema file, and AsciiDoc documentation. The PR also removes the version comparison file for 26.1.5→26.1.6 and adds a new comparison file for 26.1.6→26.1.8.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Possibly related PRs

• redpanda-data/docs#1589: Updates asciidoc.attributes.full-version and asciidoc.attributes.latest-redpanda-tag version metadata in antora.yml
• redpanda-data/docs#1655: Auto-generated version bump that modifies the same antora.yml AsciiDoc fallback attributes
• redpanda-data/docs#1666: Updates version metadata fields in antora.yml for a previous Redpanda version release

Suggested reviewers

• paulohtb6
• Feediver1
• JakeSCahill

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description is minimal and lacks required template sections including JIRA ticket reference, review deadline, page previews, and issue type checkboxes.	Add missing template sections: JIRA ticket reference, review deadline, page preview links, and check appropriate issue type checkbox (likely 'New feature' or 'Content gap').

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: updating property documentation for the v26.1.8 release tag.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch update-property-docs-v26.1.8

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[JakeSCahill]

this actually came in 26.1.7 see #1693

[JakeSCahill]

I'd suggested merging that one first, then rerunning the automation

[Feediver1]

done

[Feediver1]

Merged #1693 first and reran the v26.1.8 automation — duplicate is gone now, thanks for catching it