[stable/2023.1] keystone: Add v3websso plugin's localhost URL to trusted_dashboard [ATMOSPHERE-252] (#1417)

This is an automated cherry-pick of #1415
/assign mnaser
diff --git a/roles/keystone/vars/main.yml b/roles/keystone/vars/main.yml
index a051576..f40d858 100644
--- a/roles/keystone/vars/main.yml
+++ b/roles/keystone/vars/main.yml
@@ -45,7 +45,11 @@
         remote_id_attribute: HTTP_OIDC_ISS
       federation:
         # TODO(mnaser): Lookup using openstack_helm_endpoints
-        trusted_dashboard: "https://{{ openstack_helm_endpoints_horizon_api_host }}/auth/websso/"
+        trusted_dashboard:
+          type: multistring
+          values:
+            - "http://localhost:9990/auth/websso/"
+            - "https://{{ openstack_helm_endpoints_horizon_api_host }}/auth/websso/"
       oslo_messaging_notifications:
         driver: noop
     wsgi_keystone: |