restore .signin-with-google class for spec tests

app/views/projects/clusters/new.html.haml

@@ -23,6 +23,7 @@
         - if @valid_gcp_token
           = render 'projects/clusters/gcp/form'
         - elsif @authorize_url
+          .signin-with-google
             = link_to(image_tag('auth_buttons/signin_with_google.png', width: '191px'), @authorize_url)
             = _('or')
             = link_to('create a new Google account', 'https://accounts.google.com/SignUpWithoutGmail?service=cloudconsole&continue=https%3A%2F%2Fconsole.cloud.google.com%2Ffreetrial%3Futm_campaign%3D2018_cpanel%26utm_source%3Dgitlab%26utm_medium%3Dreferral', target: '_blank', rel: 'noopener noreferrer')