fix(#9108): block updating admin only docs

[garethbowen]

Description

#9108

Code review checklist

• Readable: Concise, well named, follows the style guide, documented if necessary.
• Documented: Configuration and user documentation on cht-docs
• Tested: Unit and/or e2e where appropriate
• Internationalised: All user facing text
• Backwards compatible: Works with existing data and configuration or includes a migration. Any breaking changes documented in the release notes.

Compose URLs

If Build CI hasn't passed, these may 404:

• Core
• CouchDB Single
• CouchDB Cluster

License

The software is provided under AGPL-3.0. Contributions to this project are accepted under the same license.

[garethbowen]

@sugat009 Can I get a review please? I won't merge this until #9107 is merged but it can be reviewed now and rebased later. Reproduction steps in the linked issue...