Fix flaky test (#12365)

Author: BrennanConroy

src/SignalR/common/Http.Connections/test/HttpConnectionDispatcherTests.cs

@@ -1772,12 +1772,11 @@ public async Task LongPollingCanPollIfWritePipeHasBackpressure()
         }
 
         [Fact]
-        [Flaky("https://github.com/aspnet/AspNetCore-Internal/issues/1975", FlakyOn.All)]
         public async Task ErrorDuringPollWillCloseConnection()
         {
             bool ExpectedErrors(WriteContext writeContext)
             {
-                return (writeContext.LoggerName == typeof(LongPollingServerTransport).FullName &&
+                return (writeContext.LoggerName.Equals("Microsoft.AspNetCore.Http.Connections.Internal.Transports.LongPollingTransport") &&
                        writeContext.EventId.Name == "LongPollingTerminated") ||
                        (writeContext.LoggerName == typeof(HttpConnectionManager).FullName &&
                        writeContext.EventId.Name == "FailedDispose");