Support a GET LRO

[lmazuel]

Because that exists, cc @weidongxu-microsoft for more details

[weidongxu-microsoft]

An example in web https://github.com/Azure/azure-rest-api-specs/blob/cf35748/specification/web/resource-manager/Microsoft.Web/stable/2022-03-01/WebApps.json#L2981

I've tested the activation operation of the API, it returns 202 with Location and Retry-After header. So it appears that service did implement an LRO for it. (I didn't test the polling, as Java core for now throws for it)

However, I didn't find any ARM document that mention the GET LRO
https://github.com/Azure/azure-resource-manager-rpc/blob/master/v1.0/async-api-reference.md

And the new LRO guideline on data-plane also not mentioning it (which likely means GET should not happen)
microsoft/api-guidelines#353