Fix tests

Author: javiercn

dotnet/src/Microsoft.Agents.AI.AGUI/Shared/AGUIChatMessageExtensions.cs

@@ -2,9 +2,7 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Text.Json;
-using System.Text.Json.Serialization.Metadata;
 using Microsoft.Extensions.AI;
 
 #if ASPNETCORE

dotnet/src/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore/AGUIJsonSerializerOptions.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft. All rights reserved.
+// Copyright (c) Microsoft. All rights reserved.
 
 using System.Text.Json;
 

dotnet/src/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore/ServiceCollectionExtensions.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft. All rights reserved.
+// Copyright (c) Microsoft. All rights reserved.
 
 using System;
 using Microsoft.Agents.AI;