Changed the DD4HEP method to layerIdx

Pr/PrKernel/include/PrKernel/PrFTZoneHandler.h

@@ -33,7 +33,7 @@ namespace FTZoneCache {
     PrFTZoneHandler( DeFT const& ftDet ) {
 #ifdef USE_DD4HEP
       auto func = [this]( const DeFTLayer& layer ) {
-        const auto id = layer.layerID();
+        const auto id = layer.layerIdx();
         // fixme
         DetectorSegment seg( 0, layer.globalZ(), layer.dxdy(), layer.dzdy(), 0., 0. );
         const auto      xmax = 0.5f * layer.sizeX();