feat: implement GetMessageBatchResultsAsync method

src/AnthropicClient/Models/ErroredMessageBatchResult.cs

@@ -0,0 +1,19 @@
+namespace AnthropicClient.Models;
+
+/// <summary>
+/// Represents a message batch result that contains an error response.
+/// </summary>
+public class ErroredMessageBatchResult : MessageBatchResult
+{
+  /// <summary>
+  /// Gets the error of the message batch result.
+  /// </summary>
+  public AnthropicError Error { get; init; } = new AnthropicError();
+
+  /// <summary>
+  /// Initializes a new instance of the <see cref="ErroredMessageBatchResult"/> class.
+  /// </summary>
+  public ErroredMessageBatchResult() : base(MessageBatchResultType.Errored)
+  {
+  }
+}