Prevent change to Auto Signal from Explorer due to clear request propagation

Author: cesarBLG

Source/Orts.Simulation/Simulation/Signalling/SignalObject.cs

@@ -2522,6 +2522,9 @@ private void propagateRequest()
             // no. of next signals to clear : as passed on -1 if signal has normal clear ahead
             // if passed on < 0, use this signals num to clear
 
+            // Do not propagate the request in explorer mode, as it is handled elsewhere
+            if (enabledTrain != null && enabledTrain.Train.ControlMode == Train.TRAIN_CONTROL.EXPLORER) return;
+
             // sections not available
             bool validPropagationRequest = true;
             if (internalBlockState > InternalBlockstate.Reservable)