How to unregister Avatars Widget?


I like the plugin but don't want my users to have access to the Avatars Widget. I know there's plugins that allow you to hide widgets but in my case I need to go beyond hiding it and unregister it. I found the code that does this but for some reason it's not affecting this plugin. Any idea on how to unregister this one?

I tried putting this in my child-theme function.php file:

function unregister_specific_widgets() {
add_action('widgets_init', 'unregister_specific_widgets', 1);