Remove explicit refresh_interval from identity-provider internal index (elastic#97835)

The preference is now to rely on the implicit refresh_interval value
when creating internal indices.

Related elastic#97815

Author: albertzaharovits

x-pack/plugin/core/src/main/resources/org/elasticsearch/xpack/idp/saml-service-provider-template.json

@@ -11,7 +11,6 @@
     "number_of_replicas": 0,
     "auto_expand_replicas": "0-1",
     "index.priority": 10,
-    "index.refresh_interval": "1s",
     "index.format": 1
   },
   "mappings": {