Person deduplication affects the original

Describe the bug

When creating duplicate person original's avatar is affected.

Steps to reproduce

1. Create person with handle test giving them an avatar
2. Attempt to create second person with the same handle, assigning them an avatar.

Expected behavior

Duplicate person not created.

Actual behavior

Duplicate person not created but original test persona gets their avatar removed.

Relevant logs and/or screenshots

N/A

Context

• Castopod: 1.9
• OS: Debian 11
• Browser: Firefox 122
• Web server: NGINX

Possible fixes

Regression from #419 (closed) ?