feat: Contact Exports (#7258)

app/mailers/administrator_notifications/channel_notifications_mailer.rb

@@ -43,6 +43,14 @@ class AdministratorNotifications::ChannelNotificationsMailer < ApplicationMailer
     send_mail_with_liquid(to: admin_emails, subject: subject) and return
   end
 
+  def contact_export_complete(file_url)
+    return unless smtp_config_set_or_development?
+
+    @action_url = file_url
+    subject = "Your contact's export file is available to download."
+    send_mail_with_liquid(to: admin_emails, subject: subject) and return
+  end
+
   private
 
   def admin_emails