Update MainDialog.cs

Author: darrenj

samples/csharp/assistants/virtual-assistant/VirtualAssistantSample/Dialogs/MainDialog.cs

@@ -121,7 +121,7 @@ protected override async Task<DialogTurnResult> OnBeginDialogAsync(DialogContext
         protected override async Task<DialogTurnResult> OnContinueDialogAsync(DialogContext innerDc, CancellationToken cancellationToken = default)
         {
             var activity = innerDc.Context.Activity;
-            
+
             // Get cognitive models for the current locale.
             var localizedServices = _services.GetCognitiveModels();
 
@@ -517,4 +517,4 @@ private bool ShouldBeginChitChatDialog(WaterfallStepContext stepContext, Dispatc
             return false;
         }
     }
-}
+}