After blocking domain with reject_media, invalidate cache (#6679)

Media attachments are part of the association cache of statuses,
since they are presumed to be immutable. Unless this cache is
cleared manually, the statuses will continue to look like they
have media embedded.

lib/tasks/mastodon.rake

@@ -476,10 +476,10 @@ namespace :mastodon do
       time_ago = ENV.fetch('NUM_DAYS') { 7 }.to_i.days.ago
 
       MediaAttachment.where.not(remote_url: '').where.not(file_file_name: nil).where('created_at < ?', time_ago).find_each do |media|
-        if media.file.exists?
-          media.file.destroy
-          media.save
-        end
+        next unless media.file.exists?
+
+        media.file.destroy
+        media.save
       end
     end