.Net Processes - Sync parameter name for error handler (#9797)

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Update sample `Step04_AgentOrchestration` to correctly specify the name
of the function parameter.

Fixes: #9778

### Description
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Sample specified parameter name `exception` but the actual name had been
refactored to `error`.

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dotnet/samples/GettingStartedWithProcesses/Step04/Step04_AgentOrchestration.cs

@@ -166,7 +166,7 @@ void AttachErrorStep(ProcessStepBuilder step, params string[] functionNames)
             {
                 step
                     .OnFunctionError(functionName)
-                    .SendEventTo(new ProcessFunctionTargetBuilder(renderMessageStep, RenderMessageStep.Functions.RenderError, "exception"))
+                    .SendEventTo(new ProcessFunctionTargetBuilder(renderMessageStep, RenderMessageStep.Functions.RenderError, "error"))
                     .StopProcess();
             }
         }