DEV: Update rubocop-discourse from 2.3.2 to 2.4.0 (#11079)

Also fixes whitespace related issues raised by rubocop.

app/models/concerns/reports/moderators_activity.rb

@@ -152,7 +152,7 @@ module Reports::ModeratorsActivity
       AND p.created_at <= '#{report.end_date}'
       GROUP BY p.user_id
       )
-    
+
       SELECT
       m.user_id,
       m.username,

app/models/concerns/reports/top_ignored_users.rb

@@ -56,7 +56,7 @@ module Reports::TopIgnoredUsers
             ORDER BY COUNT(*) DESC
             LIMIT :limit
           )
-    
+
           SELECT u.id as user_id,
                  u.username as username,
                  u.uploaded_avatar_id as uploaded_avatar_id,