adjust test assertion

Author: slobodanadamovic

x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/privileges/11_builtin.yml

@@ -16,4 +16,4 @@ setup:
   # I would much prefer we could just check that specific entries are in the array, but we don't have
   # an assertion for that
   - length: { "cluster" : 62 }
-  - length: { "index" : 22 }
+  - length: { "index" : 24 }