Fix deserialization for PutSynonymResponse

[GeorgeCiachir]

The ReloadResult should be a member of the PutResponseSynonym, instead of the ReloadDetails, so that the PutResponseSynonym is properly serialized.
Current behavior is that it throws a MissingRequiredPropertyException

Closes elastic/elasticsearch-java#784
Closes #2578

[pquentin]

Thanks @GeorgeCiachir for this. Unfortunately, our CI is not setup to accept external contributions due to security concerns, so I opened #2578 to get validation running. Which fixed validation here, so now this can be reviewed.

[GeorgeCiachir]

Thanks @GeorgeCiachir for this. Unfortunately, our CI is not setup to accept external contributions due to security concerns, so I opened #2578 to get validation running. Which fixed validation here, so now this can be reviewed.

Thanks, @pquentin
I was wondering what's up with the validation because I also wanted to validate from my local, but I got a 404 on https://github.com/elastic/clients-flight-recorder.git.
Maybe the Readme should also be updated and specify the validation part can only be performed by the Elastic team members. I mean here: https://github.com/elastic/elasticsearch-specification/tree/main?tab=readme-ov-file#how-to-validate-the-specification

[l-trotta]

LGTM, good job!