.NET: Add per run / thread feature collection support and improved custom ChatMessageStore support (#2345)

* Add the ability to override services on an agent per run.

* Remove Run from AgentFeatureCollection name.

* Adding features param to GetNewThread.

* Move feature collection.

* Add features to DeserializeThread

* Remove servicecollection based option

* Add feature collection unit tests and fix bug identified in code review.

* Add more unit tests for DelegatingAIAgent and AgentRunOptions

* Fix formatting.

* Address PR comments.

* Switch to dedicated ConversationIdAgentFeature and improve 3rd party storage samples.

* Fix bug in sample.

dotnet/src/Microsoft.Agents.AI.Abstractions/InMemoryAgentThread.cs

@@ -4,8 +4,6 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Text.Json;
-using System.Threading;
-using System.Threading.Tasks;
 using Microsoft.Extensions.AI;
 
 namespace Microsoft.Agents.AI;
@@ -116,10 +114,6 @@ public abstract class InMemoryAgentThread : AgentThread
     public override object? GetService(Type serviceType, object? serviceKey = null) =>
         base.GetService(serviceType, serviceKey) ?? this.MessageStore?.GetService(serviceType, serviceKey);
 
-    /// <inheritdoc />
-    protected internal override Task MessagesReceivedAsync(IEnumerable<ChatMessage> newMessages, CancellationToken cancellationToken = default)
-        => this.MessageStore.AddMessagesAsync(newMessages, cancellationToken);
-
     [DebuggerBrowsable(DebuggerBrowsableState.Never)]
     private string DebuggerDisplay => $"Count = {this.MessageStore.Count}";