Removes edit recipient link (#170)

This removes the edit recipient control on discussions that arent private.

Co-authored-by: Daniël Klabbers <[email protected]>

src/Api/DiscussionPermissionAttributes.php

@@ -40,7 +40,7 @@ public function __invoke(DiscussionSerializer $serializer, Discussion $model, ar
         $users = $actor->can('editUserRecipients', $model);
         $groups = $actor->can('editGroupRecipients', $model);
 
-        $attributes['canEditRecipients'] = $users || $groups;
+        $attributes['canEditRecipients'] = $model->is_private && ($users || $groups);
         $attributes['canEditUserRecipients'] = $users;
         $attributes['canEditGroupRecipients'] = $groups;