Add wait_for_no_initializing_shards to cluster health API

[cmpoon]

This PR adds wait_for_no_initializing_shards to cluster health API which has been available on all 7.x releases.

See https://www.elastic.co/guide/en/elasticsearch/reference/7.17/cluster-health.html

wait_for_no_initializing_shards (Optional, Boolean) A boolean value which controls whether to wait (until the timeout provided) for the cluster to have no shard initializations. Defaults to false, which means it will not wait for initializing shards.

[cmpoon]

Hello @olivere! 👋🏽 Is any chance you could take a quick look please? 🙏🏽