Update default storage configuration and sanity timing across all CNV scale-testing scenarios:

Storage changes:

• Change default storageClassName from ocs-storagecluster-ceph-rbd to ocs-storagecluster-ceph-rbd-virtualization in per-host-density and virt-capacity-benchmark (both full and sanity vars files)
• Add explicit volumeMode: Block to both dataVolumeTemplates (root disk and data disk) in virt-capacity-benchmark VM template

Sanity timing:

• Reduce jobPause from 1m (or 30s for per-host-density) to 10s across all 9 sanity configs — sanity mode is meant for quick validation, and the long pauses between kube-burner job phases add unnecessary wait time

Upstream PR: https://github.com/redhat-vmeperf/cnv-scenarios/pull/28