Only show back button if you’ve come from settings

You can also reach this page from the individual template view.

app/templates/views/service-settings/set-letter-contact-block.html

@@ -22,7 +22,7 @@
       ) }}
       {{ page_footer(
         'Save',
-        back_link=url_for('.service_settings', service_id=current_service.id),
+        back_link=None if request.args.get('from_template') else url_for('.service_settings', service_id=current_service.id),
         back_link_text='Back to settings'
       ) }}
     </form>