Fail fast when server returns Query error instead of while results are enumerated

In PS, if the .NET gRPC client will not throw an exeception on error until the results are enumerated. This makes it seem like call succeeds until it blows up, even if we expect failure. An example would be including a bucket name that does not exist in a query:

"SELECT * FROM NOTEXISTENTBUCKET limit 1;"

Instead, the AsyncServerStreamingCall.GetStatus() can be called can be called just after the query and the RpcExeception will be thrown.

Note: ensure that calling GetStatus() first will not load the entire response into memory causing potential OOM exceptions.