add form_update to ignored events

- this was throwing an error through translation files in the audit service calls, so form.completed and submission.completed were not firing correctly.

Author: ryanarakawa

lib/submissions/generate_audit_trail.rb

@@ -388,7 +388,7 @@ def build_audit_trail(submission)
       composer.text(I18n.t('event_log'), font_size: 12, padding: [10, 0, 20, 0])
 
       events_data = submission.submission_events.sort_by(&:event_timestamp).filter_map do |event|
-        next if event.event_type.in?(%w[bounce_email complaint_email])
+        next if event.event_type.in?(%w[bounce_email complaint_email form_update])
 
         submitter = submission.submitters.find { |e| e.id == event.submitter_id }
         submitter_name =