Test calling mail only once

We want to see if this fixes `Capybara::Node:Email.body` on
`alphagov/signon`

lib/mail/notify/mailer.rb

@@ -78,11 +78,11 @@ def view_mail(template_id, options)
 
         # we have to render the view for the message and grab the raw source, then we set that as the
         # body in the personalisation for sending to the Notify API.
-        body = mail(headers).body.raw_source
+        # body = mail(headers).body.raw_source
 
         # The 'view mail' works by sending a subject and body as personalisation options, these are
         # then used in the Notify template to provide content.
-        message.personalisation = {subject: subject, body: body}
+        # message.personalisation = {subject: subject, body: body}
 
         mail(headers) do |format|
           format.text { nil }