FEATURE: Show similar users when penalizing a user (#19334)

* FEATURE: Show similar users when penalizing a user

Moderators will be notified if other users with the same IP address
exist before penalizing a user.

* FEATURE: Allow staff to penalize multiple users

This allows staff members to suspend or silence multiple users belonging
to the same person.

app/serializers/admin_detailed_user_serializer.rb

@@ -36,7 +36,9 @@ class AdminDetailedUserSerializer < AdminUserSerializer
              :can_disable_second_factor,
              :can_delete_sso_record,
              :api_key_count,
-             :external_ids
+             :external_ids,
+             :similar_users,
+             :similar_users_count
 
   has_one :approved_by, serializer: BasicUserSerializer, embed: :objects
   has_one :suspended_by, serializer: BasicUserSerializer, embed: :objects
@@ -156,6 +158,28 @@ class AdminDetailedUserSerializer < AdminUserSerializer
     external_ids
   end
 
+  def similar_users
+    ActiveModel::ArraySerializer.new(
+      @options[:similar_users],
+      each_serializer: AdminUserListSerializer,
+      each_serializer: SimilarAdminUserSerializer,
+      scope: scope,
+      root: false,
+    ).as_json
+  end
+
+  def include_similar_users?
+    @options[:similar_users].present?
+  end
+
+  def similar_users_count
+    @options[:similar_users_count]
+  end
+
+  def include_similar_users_count?
+    @options[:similar_users].present?
+  end
+
   def can_delete_sso_record
     scope.can_delete_sso_record?(object)
   end