[Enhancement] Restoration failed due to full-snapshot taken by backup-restore is found to be corrupted or not having a hash

[ishan16696]

Enhancement (What you would like to be added): It has been observed that while doing the restoration from full snapshot, backup-restore failed to restore the etcd from full-snapshot. This failure appears to be due to some full snapshots being corrupted or missing a hash.

Logs of backup-restore during restoration.

FATA[0002] Failed to restore snapshot: failed to restore from the base snapshot: snapshot missing hash but --skip-hash-check=false 

Motivation (Why is this needed?):

1. One of such case is reported here: https://github.com/gardener/etcd-backup-restore/issues/749 by community user.
2. We have also observed such cases in our internal clusters while doing the recovery from permanent quorum loss for etcd cluster.

Approach/Hint to the implement solution (optional):

[ishan16696]

/assign