Change Cloudshell request method from POST to GET

[Avery-Dunn]

Testing by the Azure SDK team has shown an issue when making the POST request for Cloudshell, where the server responds with a error message saying the resource is missing from the request. This only occurs when using Netty, a common networking framework for Java, and POST requests work fine in other MSALs.

However, further testing has shown it works fine in Netty and other common frameworks if it is a GET request with resource as a query parameter, and this PR makes that change as a workaround. This change should not affect any existing working customers, and we should be able to swap back to a POST request in the future if we need to.

[rayluo]

when making the POST request for Cloudshell, where the server responds with a error message saying the resource is missing from the request. This only occurs when using Netty, a common networking framework for Java, and POST requests work fine in other MSALs.

That sounds so weird. HTTP stuffs are supposed to be language and platform-agnostic.

Can we have a short(est) code snippet written with Netty to repro that? That way, we can then have either Cloud Shell folks or Netty folks to troubleshoot to see whether it is a bug on their sides.