Route notifications to groups for EE mailers

ee/app/mailers/ee/emails/projects.rb

@@ -5,24 +5,21 @@ module EE
     module Projects
       def mirror_was_hard_failed_email(project_id, user_id)
         @project = ::Project.find(project_id)
-        user = ::User.find(user_id)
 
-        mail(to: user.notification_email,
+        mail(to: recipient(user_id, @project.group),
              subject: subject('Repository mirroring paused'))
       end
 
       def project_mirror_user_changed_email(new_mirror_user_id, deleted_user_name, project_id)
         @project = ::Project.find(project_id)
         @deleted_user_name = deleted_user_name
-        new_mirror_user = ::User.find(new_mirror_user_id)
 
-        mail(to: new_mirror_user.notification_email,
+        mail(to: recipient(new_mirror_user_id, @project.group),
              subject: subject('Mirror user changed'))
       end
 
       def prometheus_alert_fired_email(project_id, user_id, alert_payload)
         @project = ::Project.find(project_id)
-        user = ::User.find(user_id)
 
         @alert = ::Gitlab::Alerting::Alert
           .new(project: @project, payload: alert_payload)
@@ -30,7 +27,7 @@ module EE
         return unless @alert.valid?
 
         subject_text = "Alert: #{@alert.email_subject}"
-        mail(to: user.notification_email, subject: subject(subject_text))
+        mail(to: recipient(user_id, @project.group), subject: subject(subject_text))
       end
     end
   end

ee/app/mailers/emails/csv_export.rb

@@ -10,7 +10,7 @@ module Emails
 
       filename = "#{project.full_path.parameterize}_issues_#{Date.today.iso8601}.csv"
       attachments[filename] = { content: csv_data, mime_type: 'text/csv' }
-      mail(to: user.notification_email, subject: subject("Exported issues")) do |format|
+      mail(to: recipient(user.id, @project.group), subject: subject("Exported issues")) do |format|
         format.html { render layout: 'mailer' }
         format.text { render layout: 'mailer' }
       end

ee/app/mailers/emails/epics.rb

@@ -35,7 +35,7 @@ module Emails
     def epic_thread_options(sender_id, recipient_id, reason)
       {
         from: sender(sender_id),
-        to: recipient(recipient_id),
+        to: recipient(recipient_id, @epic.group),
         subject: subject("#{@epic.title} (#{@epic.to_reference})"),
         'X-GitLab-NotificationReason' => reason
       }

ee/app/mailers/emails/reviews.rb

@@ -13,7 +13,7 @@ module Emails
     def review_thread_options(recipient_id)
       {
         from: sender(@author.id),
-        to: recipient(recipient_id),
+        to: recipient(recipient_id, @merge_request.target_project.group),
         subject: subject("#{@merge_request.title} (#{@merge_request.to_reference})")
       }
     end