Suppress warning in PsesInternalHostTests

While we could put the entire task inside the lambda, thus eliminating
the warning, we then lose the ability to assert that the task itself was
cancelled. This feels important to be able to do since the exception
does not necessarily prove that this explicit task was canceled.

Author: andyleejordan

test/PowerShellEditorServices.Test/Session/PsesInternalHostTests.cs

@@ -94,6 +94,7 @@ await Assert.ThrowsAsync<TaskCanceledException>(() =>
         }
 
         [Fact]
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "VSTHRD003:Avoid awaiting foreign Tasks", Justification = "Explicitly checking task cancellation status.")]
         public async Task CanCancelExecutionWithMethod()
         {
             var executeTask = psesHost.ExecutePSCommandAsync(