fixing OperatorPrivilegesIT

Author: masseyke

x-pack/plugin/security/qa/operator-privileges-tests/src/javaRestTest/java/org/elasticsearch/xpack/security/operator/Constants.java

@@ -610,6 +610,7 @@ public class Constants {
         "indices:data/write/update",
         "indices:data/write/update/byquery",
         "indices:monitor/data_stream/settings/get",
+        "indices:monitor/data_stream/settings/update",
         "indices:monitor/data_stream/stats",
         "indices:monitor/field_usage_stats",
         "indices:monitor/fleet/global_checkpoints[s]",