Inconsistent behaviour when admin or user is deleting a user avatar

Issue Summary

This is reproducible on Data Center: (yes) 

In Confluence 8.9 we introduced ability for users to delete their user avatars. However, this endpoint only deletes user avatars created in Confluence ui. This may create issues for third party plugin vendors who may be creating user avatars with a different versionComment and is not consistent with the existing behaviour when admin deletes a user avatar via user management.

Steps to Reproduce

1. Create a new user avatar via one of third party plugins
2. Go to Profile image -> Remove avatar

Expected Results

Deleting user avatar by user should delete all attachments linked to their profile, not just the ones created in Confluence UI.

Actual Results

User avatars created by plugin vendors will not be deleted if versionComment is not "Uploaded Profile Picture".

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available