Bug: Cannot set-cover for Recognize person if the person's name matches a Nextcloud username

[gergoe]

Describe the bug

When attempting to set a cover image for a person in the Recognize tab of Memories, the API returns a 404 Not found with the message {"message":"Not found (photo)"} in the console. This only happens if the name of the person matches an actual, existing Nextcloud username on the server (even if all the photos are strictly owned by the logged-in admin user). If the person is renamed to anything else (e.g., from John to John2), the API call succeeds immediately.

Steps To Reproduce

1. Have a Nextcloud user named John.
2. As the admin user (who owns all the photos), go to Memories -> People.
3. Rename any face to John.
4. Try to set a cover image for John. The network console shows: POST /index.php/apps/memories/api/clusters/recognize/set-cover -> 404 Not Found
5. Rename the person to John2 and try setting the cover image again.
6. It works perfectly.

Platform

- OS: Ubuntu/Windows
- Browser: Firefox
- Memories Version: 8.0.1
- Nextcloud Version: 33.0.6 (Bare metal)
- PHP Version: 8.4

Screenshots

No response

Additional context

Appears to be related to #1310 as far as I can tell.