fix: avoid infinite loop on rate limit

src/Discord.Net.Rest/Net/Queue/RequestQueueBucket.cs

@@ -193,6 +193,8 @@ namespace Discord.Net.Queue
 #endif
                         if (millis > 0)
                             await Task.Delay(millis, request.Options.CancelToken).ConfigureAwait(false);
+                        else
+                            return;
                     }
                     else
                     {