[cern] Added ceph-csi-cephfs.enabled Helm binding

This MR adds ceph-csi-cephfs.enabled: $CEPHFS_CSI_ENABLED to the generated Helm values for the umbrella chart.

OS-13799

magnum/drivers/common/templates/kubernetes/helm/cern-chart.sh

@@ -92,6 +92,8 @@ ${NVIDIA_GPU_VALUES}
       enabled: ${LANDB_SYNC_ENABLED}
     prometheus-cern:
       enabled: ${CERN_CENTRAL_MONITORING}
+    ceph-csi-cephfs:
+      enabled: ${CEPHFS_CSI_ENABLED}
     openstack-cinder-csi:
       enabled: ${CINDER_CSI_ENABLED}
     base: