`InvalidOperationException` saving lane connection data

[krzychu124]

Other places where ValidateLane is used are ok.

Stacktrace

```cs Info 6,142.5260298: Saving Mod Data. Error 6,142.5392794: Error occurred while saving data: System.InvalidOperationException: out of sync at System.Collections.Generic.Dictionary`2+Enumerator[TrafficManager.Manager.Impl.LaneConnection.LaneEnd,TrafficManager.Manager.Impl.LaneConnection.LaneConnectionData[]].VerifyState () [0x00000] in :0 at System.Collections.Generic.Dictionary`2+Enumerator[TrafficManager.Manager.Impl.LaneConnection.LaneEnd,TrafficManager.Manager.Impl.LaneConnection.LaneConnectionData[]].MoveNext () [0x00000] in :0 at TrafficManager.Manager.Impl.LaneConnection.LaneConnectionSubManager.SaveData (System.Boolean& success) [0x00000] in :0 at TrafficManager.Manager.Impl.LaneConnection.LaneConnectionManager.SaveData (System.Boolean& success) [0x00000] in :0 at TrafficManager.Lifecycle.SerializableDataExtension.Save () [0x00000] in :0 at CSUtil.Commons.Log.LogToFile(System.String log, LogLevel level) at CSUtil.Commons.Log.Error(System.String s) at TrafficManager.Lifecycle.SerializableDataExtension.Save() at TrafficManager.Lifecycle.SerializableDataExtension.OnSaveData() at SerializableDataWrapper.OnSaveData() at SimulationManager+Data.Serialize(ColossalFramework.IO.DataSerializer s) at ColossalFramework.IO.DataSerializer.Serialize(System.IO.Stream stream, Mode mode, UInt32 version, IDataContainer data) at LoadingManager+c__IteratorC.MoveNext() at AsyncTask.Execute() at SimulationManager.SimulationStep() at SimulationManager.SimulationThread() ```