chore: remove node subnet cilium version tag

Author: santhoshmprabhu

.pipelines/singletenancy/cilium-nodesubnet/cilium-nodesubnet-e2e-step-template.yaml

@@ -57,7 +57,6 @@ steps:
         pwd
         kubectl cluster-info
         kubectl get po -owide -A
-        CILIUM_VERSION_TAG=${CILIUM_NODE_SUBNET_VERSION}
         echo "install Cilium ${CILIUM_VERSION_TAG}"
         export DIR=${CILIUM_VERSION_TAG%.*}
         echo "installing files from ${DIR}"