Fix conversation deserialization issue

Author: JC-386

sdk/agentserver/Azure.AI.AgentServer.AgentFramework/src/Converters/RequestConverterExtensions.cs

@@ -59,7 +59,7 @@ public static IReadOnlyCollection<ChatMessage> GetInputMessages(this CreateRespo
                         var content = rawContent == null
                             ? null
                             : rawContent.ToObject<IList<ItemContent>>() ??
-                              [new ItemContentInputText(rawContent.ToString())];
+                              [new ItemContentInputText(rawContent.ToObject<string>())];
 
                         var aiContents = (content ?? ReadOnlyCollection<ItemContent>.Empty)
                             .Select(c => c is ItemContentInputText textContent ? textContent : null)
@@ -74,7 +74,7 @@ public static IReadOnlyCollection<ChatMessage> GetInputMessages(this CreateRespo
             return messages as IReadOnlyCollection<ChatMessage>;
         }
 
-        var strMessage = request.Input.ToString();
+        var strMessage = request.Input.ToObject<string>();
         return [new ChatMessage(ChatRole.User, strMessage)];
     }
 

sdk/agentserver/Azure.AI.AgentServer.Core/src/Responses/Invocation/ResponsesExtensions.cs

@@ -91,6 +91,6 @@ public static Contracts.Generated.Responses.Response ToResponse(
     /// <returns>The conversation ID, or null if not present.</returns>
     public static string? GetConversationId(this CreateResponseRequest request)
     {
-        return request.Conversation?.ToObject<ResponseConversation1>()?.Id ?? request.Conversation?.ToString();
+        return request.Conversation?.ToObject<ResponseConversation1>()?.Id ?? request.Conversation?.ToObject<string>();
     }
 }

sdk/agentserver/Azure.AI.AgentServer.Core/tests/Agents.Customized.Integration.Tests/CustomizedAgentInvocation.cs

@@ -110,7 +110,7 @@ private static string GetInputText(CreateResponseRequest request)
         }
 
         // implicit user message of text input
-        return request.Input.ToString();
+        return request.Input.ToObject<string>() ?? string.Empty;
     }
 
     private static Response ToResponse(CreateResponseRequest request, AgentInvocationContext context,