Add support for infinite ack timeout

[DaveCTurner]

The ?master_node_timeout query param supports -1 to mean¹ that the request waits forever without timing out. The ack timeout specified by the ?timeout query param also supports -1, but today this means the same as 0, i.e. that the wait for acks times out immediately. We should align the behaviour of these parameters so that users can specify that they want to wait forever for a cluster state update request to complete by setting them both to -1.

Footnotes

1. unless there's currently no master, and some other corner cases, see https://github.com/elastic/elasticsearch/pull/107050 for fix ↩

[elasticsearchmachine]

Pinging @elastic/es-distributed (Team:Distributed)

[DaveCTurner]

Closed by #107675