Reviewer request: [IGNITE-13138] Add REST tests for the new cluster state change API

[antonovsergey93]

Hello, Igniters!

I'd like to get a review of the ticket [1]. The patch is ready [2].
Can someone look at it, please?

[1] https://issues.apache.org/jira/browse/IGNITE-13138
[2] https://github.com/apache/ignite/pull/7918/files
--
BR, Sergey Antonov