.Net: Bug: Kernel.AddOpenAIChatClient with default httpClient produces error

[cyril265]

Describe the bug
After Kernel.AddOpenAIChatClient, invokePrompt produces an exception. This fixed by providing a HttpClient as a parameter to AddOpenAIChatClient.

To Reproduce

    private const string ApiKey = "secret";
    private const string Endpoint =
        "https://mistral-small-3-2-24b-instruct-2506.endpoints.kepler.ai.cloud.ovh.net/api/openai_compat/v1";
    private const string Model = "Mistral-Small-3.2-24B-Instruct-2506";


    [Fact]
    public async Task ProducesException()
    {
        var kernel = Kernel.CreateBuilder()
            .AddOpenAIChatClient(
                modelId: Model,
                apiKey: ApiKey,
                endpoint: new Uri(Endpoint)
            )
            .Build();
        KernelArguments arguments = new() { { "topic", "sea" } };
        Console.WriteLine(await kernel.InvokePromptAsync("What color is the {{$topic}}?", arguments));
    }

    [Fact]
    public async Task Works()
    {
        var kernel = Kernel.CreateBuilder()
            .AddOpenAIChatClient(
                httpClient: new HttpClient
                {
                    BaseAddress = new Uri(Endpoint)
                },
                modelId: Model,
                apiKey: ApiKey
            )
            .Build();

        KernelArguments arguments = new() { { "topic", "sea" } };
        Console.WriteLine((await kernel.InvokePromptAsync("What color is the {{$topic}}?", arguments)).ToString());
    }

   // manually creating the client without Kernel also works
    [Fact]
    public async Task CreateChatClient()
    {
        var client = new OpenAIClient(new ApiKeyCredential(ApiKey), new OpenAIClientOptions
        {
            Endpoint = new Uri(Endpoint),
        });

        var chatClient = client.GetChatClient(Model);
        var completeChat = chatClient.CompleteChat([new UserChatMessage("hello")]);
        Console.WriteLine(completeChat.Value.Content.First().Text);
    }

Full stacktrace

System.ClientModel.ClientResultException
The SSL connection could not be established, see inner exception.
   at System.ClientModel.Primitives.HttpClientPipelineTransport.ProcessSyncOrAsync(PipelineMessage message, Boolean async)
   at System.ClientModel.Primitives.HttpClientPipelineTransport.ProcessCoreAsync(PipelineMessage message)
   at System.ClientModel.Primitives.PipelineTransport.ProcessSyncOrAsync(PipelineMessage message, Boolean async)
   at System.ClientModel.Primitives.PipelineTransport.ProcessAsync(PipelineMessage message)
   at System.ClientModel.Primitives.PipelineTransport.ProcessAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at System.ClientModel.Primitives.PipelinePolicy.ProcessNextAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at System.ClientModel.Primitives.MessageLoggingPolicy.ProcessSyncOrAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex, Boolean async)
   at System.ClientModel.Primitives.MessageLoggingPolicy.ProcessAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at System.ClientModel.Primitives.PipelinePolicy.ProcessNextAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at System.ClientModel.Primitives.ApiKeyAuthenticationPolicy.ProcessAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at System.ClientModel.Primitives.PipelinePolicy.ProcessNextAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at System.ClientModel.Primitives.ClientRetryPolicy.ProcessSyncOrAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex, Boolean async)
   at System.ClientModel.Primitives.ClientRetryPolicy.ProcessSyncOrAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex, Boolean async)
   at System.ClientModel.Primitives.ClientRetryPolicy.ProcessAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at GenericActionPipelinePolicy.ProcessAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at OpenAI.GenericActionPipelinePolicy.ProcessAsync(PipelineMessage message, IReadOnlyList`1 pipeline, Int32 currentIndex)
   at System.ClientModel.Primitives.ClientPipeline.SendAsync(PipelineMessage message)
   at OpenAI.ClientPipelineExtensions.ProcessMessageAsync(ClientPipeline pipeline, PipelineMessage message, RequestOptions options)
   at OpenAI.Chat.ChatClient.CompleteChatAsync(BinaryContent content, RequestOptions options)
   at OpenAI.Chat.ChatClient.CompleteChatAsync(IEnumerable`1 messages, ChatCompletionOptions options, CancellationToken cancellationToken)
   at Microsoft.Extensions.AI.OpenAIChatClient.GetResponseAsync(IEnumerable`1 messages, ChatOptions options, CancellationToken cancellationToken)
   at Microsoft.Extensions.AI.OpenTelemetryChatClient.GetResponseAsync(IEnumerable`1 messages, ChatOptions options, CancellationToken cancellationToken)
   at Microsoft.Extensions.AI.FunctionInvokingChatClient.GetResponseAsync(IEnumerable`1 messages, ChatOptions options, CancellationToken cancellationToken)
   at Microsoft.SemanticKernel.KernelFunctionFromPrompt.GetChatClientResultAsync(IChatClient chatClient, Kernel kernel, PromptRenderingResult promptRenderingResult, CancellationToken cancellationToken)
   at Microsoft.SemanticKernel.KernelFunctionFromPrompt.InvokeCoreAsync(Kernel kernel, KernelArguments arguments, CancellationToken cancellationToken)
   at Microsoft.SemanticKernel.KernelFunction.<>c__DisplayClass32_0.<<InvokeAsync>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.SemanticKernel.Kernel.InvokeFilterOrFunctionAsync(NonNullCollection`1 functionFilters, Func`2 functionCallback, FunctionInvocationContext context, Int32 index)
   at Microsoft.SemanticKernel.Kernel.OnFunctionInvocationAsync(KernelFunction function, KernelArguments arguments, FunctionResult functionResult, Boolean isStreaming, Func`2 functionCallback, CancellationToken cancellationToken)
   at Microsoft.SemanticKernel.KernelFunction.InvokeAsync(Kernel kernel, KernelArguments arguments, CancellationToken cancellationToken)
   at SemanticKernelRag.Tests.TestiTest.ProducesException()

Expected behavior
Should work without providing a HttpClient. Seems like the HttpClient that is created inside the configure is buggy.

Platform

• Language: C#
• Versions

     <PackageReference Include="Microsoft.SemanticKernel.Agents.OpenAI" Version="1.65.0-preview" />
     <PackageReference Include="Microsoft.SemanticKernel.Connectors.OpenAI" Version="1.65.0" />