fix: update generated rpc requests to not omit ConfigureAwait(false)

[robcao]

What was changed

Updates the code generated rpc calls to just return the Task<Resp> instead of awaiting.

Why?

The current code is being awaited without a ConfigureAwait(false), which can cause deadlocks when being invoked inside synchronization contexts such as WindowsFormsSynchronizationContext.

Checklist

1. Closes
   No issue created, discussed with Chad on Slack, could create an issue if desired.

2. How was this tested:

I ran the existing tests locally and made sure they passed.

I could add a windows-only test for this if wanted, but this is very edge case and there are a few msbuild property changes needed to get WinForms into .net6 that would have to be windows-only.

Or I guess I could write a custom SynchronizationContext that does essentially the same thing, and use it for a test?

The deadlock can be simulated by running this console application on a Windows machine:

using System;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WinFormsRepro
{
	public class Program
	{
		public static async Task Main(string[] args)
		{
			SynchronizationContext.SetSynchronizationContext(new WindowsFormsSynchronizationContext());

			Console.Out.WriteLine("About to call the workflow service!");

			await SimulateWorkflowServiceRpcAsync().ConfigureAwait(false);

			Console.Out.WriteLine("Finished calling the workflow service.");
		}


		public static async Task SimulateWorkflowServiceRpcAsync() => await SimulateTemporalRpcCallAsync();

		public static async Task SimulateTemporalRpcCallAsync()
		{
			var completion = new TaskCompletionSource<string>();

			Task task = Task.Run(() =>
			{
				Thread.Sleep(100);
				completion.SetResult("complete");
			});

			await task.ConfigureAwait(false);

		}
	}

}

with the following .csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0-windows</TargetFramework>
    <UseWindowsForms>true</UseWindowsForms>
  </PropertyGroup>

</Project>

I tested that changing SimulateWorkflowServiceRpcAsync to the following does not deadlock.

public static Task SimulateWorkflowServiceRpcAsync() => SimulateTemporalRpcCallAsync();

3. Any docs updates needed?

No

[cretz]

Looks great, will merge if/when CI passes (I am merging main into your branch first).