Fix possible test failure for bwc with earlier versions, e.g. 7.0 (#63053)

In earlier versions, e.g. 7.0, creation of API keys mandate the role_descriptors field.
This PR ensure role_descriptors field is always specified.
Also the watcher created with the API key has interval of 1s and throttle of 1s as well.
In rare cases, the watcher state may happen to be throttled instead of executed during
the assertion period. This PR reduces the throttle to 500ms.

Author: ywangd

x-pack/qa/full-cluster-restart/src/test/java/org/elasticsearch/xpack/restart/FullClusterRestartIT.java

@@ -216,7 +216,8 @@ public void testWatcherWithApiKey() throws Exception {
 
         if (isRunningAgainstOldCluster()) {
             final Request createApiKeyRequest = new Request("PUT", "/_security/api_key");
-            createApiKeyRequest.setJsonEntity("{\"name\":\"key-1\"}");
+            createApiKeyRequest.setJsonEntity("{\"name\":\"key-1\",\"role_descriptors\":" +
+                "{\"r\":{\"cluster\":[\"all\"],\"indices\":[{\"names\":[\"*\"],\"privileges\":[\"all\"]}]}}}");
             final Response response = client().performRequest(createApiKeyRequest);
             final Map<String, Object> createApiKeyResponse = entityAsMap(response);
 

x-pack/qa/full-cluster-restart/src/test/resources/org/elasticsearch/xpack/restart/logging-watch.json

@@ -16,7 +16,7 @@
       }
     }
   },
-  "throttle_period": "1s",
+  "throttle_period_in_millis": 500,
   "actions" : {
     "log" : {
       "logging" : {