delete StatusCode.ClientTransportTimeout status code on pool has been exhausted

Author: KirillKurdyukov

src/Ydb.Sdk/src/Ado/Session/PoolingSessionSource.cs

@@ -127,10 +127,9 @@ private async ValueTask<ISession> RentAsync(CancellationToken cancellationToken)
             }
 
             await using var _ = finalToken.Register(() => waiterTcs.TrySetException(
-                    new YdbException(StatusCode.ClientTransportTimeout,
-                        $"The connection pool has been exhausted, either raise 'MaxSessionPool' " +
-                        $"(currently {_maxSessionSize}) or 'CreateSessionTimeout' " +
-                        $"(currently {_createSessionTimeout} seconds) in your connection string.")
+                    new YdbException($"The connection pool has been exhausted, either raise 'MaxSessionPool' " +
+                                     $"(currently {_maxSessionSize}) or 'CreateSessionTimeout' " +
+                                     $"(currently {_createSessionTimeout} seconds) in your connection string.")
                 ), useSynchronizationContext: false
             );
             await using var disposeRegistration = _disposeCts.Token.Register(