Add protection for photons with no layer 1 EM clusters for pointing tool

The photon pointing tool might run over photons which don't have any EM1 cluster. This would trigger a warning from the ShowerDepthTool. https://gitlab.cern.ch/atlas/athena/-/blob/main/Reconstruction/egamma/egammaUtils/Root/ShowerDepthTool.cxx#L111

To avoid this an early check is added here, returning the same value as the ShowerDepthTool would but avoiding the warning.

FYI @christos @atishelm @gdigrego

Reconstruction/egamma/egammaUtils/Root/egPhotonWrtPoint.cxx

@@ -9,8 +9,9 @@
 
 photonWrtPoint::PtEtaPhi photonWrtPoint::PtEtaPhiWrtZ(const xAOD::Egamma& ph,
                                                       double z) {
-  std::pair<double, float> RZ1 =
-      CP::ShowerDepthTool::getRZ(ph.caloCluster()->etaBE(1), 1);
+  std::pair<double, float> RZ1 = {0., 0.};
+  float etaBE1 = ph.caloCluster()->etaBE(1);
+  if(std::abs(etaBE1) < 10) RZ1 = CP::ShowerDepthTool::getRZ(etaBE1, 1);
 
   double rCalo = RZ1.first;
   double zCalo = RZ1.second;