Fix DD4HEP build
Since the merge of !691 (merged), DD4HEP builds of Allen fail (see https://lhcb-nightlies.web.cern.ch/nightly/lhcb-master-mr/4905/Allen/x86_64_v2-centos7-gcc11%2Bdd4hep-opt/build). These errors should be fixed as soon as possible.
Since the merge of !691 (merged), DD4HEP builds of Allen fail (see https://lhcb-nightlies.web.cern.ch/nightly/lhcb-master-mr/4905/Allen/x86_64_v2-centos7-gcc11%2Bdd4hep-opt/build). These errors should be fixed as soon as possible.