Stop passing dvla_org_id to template preview

We were passing both dvla_org_id and filename to template-preview
temporarily while we switch to only using filename. Now that
template-preview is set up to use the filename, we can stop sending the
dvla_org_id too.

app/celery/letters_pdf_tasks.py

@@ -53,7 +53,6 @@ def create_letters_pdf(self, notification_id):
         pdf_data, billable_units = get_letters_pdf(
             notification.template,
             contact_block=notification.reply_to_text,
-            org_id=notification.service.dvla_organisation.id,
             filename=notification.service.dvla_organisation.filename,
             values=notification.personalisation
         )
@@ -80,7 +79,7 @@ def create_letters_pdf(self, notification_id):
             update_notification_status_by_id(notification_id, 'technical-failure')
 
 
-def get_letters_pdf(template, contact_block, org_id, filename, values):
+def get_letters_pdf(template, contact_block, filename, values):
     template_for_letter_print = {
         "subject": template.subject,
         "content": template.content
@@ -91,7 +90,6 @@ def get_letters_pdf(template, contact_block, org_id, filename, values):
         'template': template_for_letter_print,
         'values': values,
         'filename': filename,
-        'dvla_org_id': org_id,
     }
     resp = requests_post(
         '{}/print.pdf'.format(

app/template/rest.py

@@ -248,7 +248,6 @@ def preview_letter_template_by_notification_id(service_id, notification_id, file
             'values': notification.personalisation,
             'date': notification.created_at.isoformat(),
             'filename': service.dvla_organisation.filename,
-            'dvla_org_id': service.dvla_organisation_id,
         }
 
         url = '{}/preview.{}{}'.format(