Make `can_send_from_user_email?` public in Notify

app/mailers/notify.rb

@@ -33,13 +33,13 @@ class Notify < BaseMailer
     allowed_domains
   end
 
-  private
-
   def can_send_from_user_email?(sender)
     sender_domain = sender.email.split("@").last
     self.class.allowed_email_domains.include?(sender_domain)
   end
 
+  private
+
   # Return an email address that displays the name of the sender.
   # Only the displayed name changes; the actual email address is always the same.
   def sender(sender_id, send_from_user_email = false)