Update .NET isolated templates to make sure we're using async patterns when working with HttpRequestData

[kshyju]

Update .NET isolated templates to make sure we're using async patterns when working with HttpRequestData

See Azure/azure-functions-dotnet-worker#2184

[ChristopherL-STCU]

I just hit this when using the DurableFunctionsOrchestration-CSharp-Isolated. I received the error:

Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead

After researching this I understood I needed to update CreateCheckStatusResponse to CreateCheckStatusResponseAsync.

[EntityAdam]

Ran into this issue with the out-of-box experience. Terrible developer experience.

Track fix here: #1512