Remove support for old request attribute on event objects

src/Stripe.net/Entities/Events/Event.cs

@@ -30,27 +30,8 @@ public class Event : StripeEntity, IHasId, IHasObject
         [JsonProperty("pending_webhooks")]
         public int PendingWebhooks { get; set; }
 
-        #region Request
-
-        /*
-         * This works like expandable properties. it's used for the event having just a string for the request id or
-         * the Request object for requests after the 2017-05-25 api release
-         */
-
-        public string RequestId { get; set; }
-
-        [JsonIgnore]
-        public EventRequest Request { get; set; }
-
         [JsonProperty("request")]
-        internal object InternalRequest
-        {
-            set
-            {
-                StringOrObject<EventRequest>.Map(value, s => this.RequestId = s, o => this.Request = o);
-            }
-        }
-        #endregion
+        public EventRequest Request { get; set; }
 
         [JsonProperty("type")]
         public string Type { get; set; }