Update to latest Agent pattern

Author: markwallace-microsoft

dotnet/samples/Demos/ModelContextProtocolPlugin/Program.cs

@@ -73,21 +73,14 @@
 Console.WriteLine($"\n\n{prompt}\n{result}");
 
 // Define the agent
-ChatCompletionAgent agent =
-new()
+ChatCompletionAgent agent = new()
 {
     Instructions = "Answer questions about GitGub repositories.",
     Name = "GitHubAgent",
     Kernel = kernel,
     Arguments = new KernelArguments(new PromptExecutionSettings() { FunctionChoiceBehavior = FunctionChoiceBehavior.Auto() }),
 };
 
-/// Create the chat history thread to capture the agent interaction.
-AgentThread thread = new ChatHistoryAgentThread();
-
 // Respond to user input, invoking functions where appropriate.
-Console.WriteLine("\n\nResponse from GitHubAgent:");
-await foreach (ChatMessageContent response in agent.InvokeAsync("Summarize the last four commits to the microsoft/semantic-kernel repository?", thread))
-{
-    Console.WriteLine(response.Content);
-}
+ChatMessageContent response = await agent.InvokeAsync("Summarize the last four commits to the microsoft/semantic-kernel repository?").FirstAsync();
+Console.WriteLine($"\n\nResponse from GitHubAgent:\n{response.Content}");