title: Unable to configure SAML Single Logout url in Google Cloud Identity Platform SAML provider
body: <p>We are using SAML provider in GCIP (SP) to integrate with Salesforce as external IDP. Our web application authentication happens via Firebase app (google identity toolkit proj) and works as expected.<br>
  We want to destroy GCIP session and SAML SSO session when the user clicks on logout in application. <br>
  We do not see any configurable property on SAML provider setting in GCIP to provider SAML Single Logout url. <br>
  Invoking /gcp-iap-mode=GCIP_SIGNOUT shows that signout is happening but it is reauthenticating the user without credentials being requested. <br>
  How can we achieve logout so that user will be forced to login again?</p>