Add IsAccepted to non-generic ElicitResult.

Author: mehrandvd

src/ModelContextProtocol.Core/Protocol/ElicitResult.cs

@@ -33,6 +33,15 @@ public sealed class ElicitResult : Result
     [JsonPropertyName("action")]
     public string Action { get; set; } = "cancel";
 
+    /// <summary>
+    /// Convenience indicator for whether the elicitation was accepted by the user.
+    /// </summary>
+    /// <remarks>
+    ///  Indicates that the elicitation request completed successfully and value of <see cref="Content"/> has been populated with a value.
+    /// </remarks>
+    [JsonIgnore]
+    public bool IsAccepted => string.Equals(Action, "accept", StringComparison.OrdinalIgnoreCase);
+
     /// <summary>
     /// Gets or sets the submitted form data.
     /// </summary>