[TEST] Update REST client before each test in our REST tests

In #7723 we removed the `updateAddresses` method from `RestClient` under the assumption that the addresses never change during the suite execution, as REST tests rely on the global cluster. Due to #6734 we restart the global cluster though before each test if there was a failure in the suite. If that happens we do need to make sure that the REST client points to the proper nodes. What was missing before was the http call to verify the es version every time the addresses change, which we do now since we effectively re-initialize the REST client when needed (if the http addresses have changed).