LHCb::Calo::ClusterCovarianceMatrixTool - Issue accessing CALO geometry in DD4HEP

Now that access to the depreciated DetDesc DBs has been prevented in the DD4HEP builds, a number of issues are showing up. See

https://lhcb-nightlies.web.cern.ch/nightly/lhcb-master-mr/4312/Moore/x86_64_v2-centos7-gcc11%2Bdd4hep-opt/tests#RecoConf.hlt2_reco_calo_only

CaloFutureClusterCovarianceAlg.E...   FATAL LHCb::Calo::ClusterCovarianceMatrixTool:: Exception throw: get():: No valid data at '/world/DownstreamRegion/Ecal' StatusCode=FAILURE
CaloFutureClusterCovarianceAlg.E...   FATAL  Exception with tag= is caught
CaloFutureClusterCovarianceAlg.E...   ERROR  	 CaloFutureClusterCovarianceAlg.EcalCovarTool:: get():: No valid data at '/world/DownstreamRegion/Ecal'	 StatusCode=FAILURE