Fix example test failure

Author: lcawl

docs/reference/rest-api/usage.asciidoc

@@ -231,7 +231,8 @@ GET /_xpack/usage
   },
   "eql" : {
     "available" : true,
-    "enabled" : true
+    "enabled" : true,
+    ...
   },
   "esql" : {
     "available" : true,
@@ -529,7 +530,10 @@ GET /_xpack/usage
     "available": true,
     "enabled": false,
     "indices_count": 0,
-    "indices_with_synthetic_source": 0
+    "indices_with_synthetic_source": 0,
+    "num_docs": 0,
+    "size_in_bytes": 0,
+    "has_custom_cutoff_date": false
   }
 }
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