MM Trigger Simulation: complete removal of AGDD dependencies

Removing all instances of AGDD from MM trigger simulation code, reflecting changes already done in main

This MR paves the way to other, future MRs in order to align 24.0 and main branches, avoiding conflicts when merging automatically. Thanks to @jojungge and @lmonaco to help sorting this out

MuonSpectrometer/MuonDetDescr/MuonReadoutGeometry/src/MMReadoutElement.cxx

 /*
-  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
 */
 
 /***************************************************************************
@@ -59,6 +59,17 @@ namespace MuonGM {
         setIdentifier(id);
         bool foundShape = false;
 
+        const PVConstLink pvc {getMaterialGeom()};
+        const GeoTrd* trd=dynamic_cast<const GeoTrd *> (pvc->getLogVol()->getShape());
+        if (trd) {
+            setSsize(2*trd->getYHalfLength1());
+            setLongSsize( 2*trd->getYHalfLength2());
+            setRsize(2*trd->getZHalfLength());
+            setZsize(trd->getXHalfLength1());
+        } else {
+            ATH_MSG_DEBUG("Not a valid GeoTrd");
+        }
+
         if (!mgr->MinimalGeoFlag()) {
             if (GeoFullPhysVol* pvc = dynamic_cast<GeoFullPhysVol*>(pv)) {
                 const GeoLogVol *lvol=pvc->getLogVol();