How do I Disable Avatar Uploading and allow users to pick from default avatars?

Hello,

I have a site with legacy_member_templates enabled, and I would like to disable allow_avatar_uploads so that my users are forced to pick from the default_set folder. Documentation says that this should be as simple as toggling a setting in the Control Panel, but the Avatar Settings page in my CP does not have either the “Allow avatars?” or “Allow avatar uploads?” options.

I tried doing a System Configuration Override for $config['allow_avatar_uploads'] = 'n';, but that didn’t work.

For context, I am running a fresh install of 6.0.6. Any help is greatly appreciated!

—DXC