CSI Sanity fails on invalid snapshot CRN/ID , this is forcing us to return success.

[sameshai]

CSI Sanity expects the DeleteSnapshot call to fail even if the snapshotID is invalid. Ideally we should return failure as we dont want to endup in situation were we have dangling snapshots in case invalid CRN format is given.

Please investigate what we can do to improve this

https://github.com/IBM/ibm-vpc-file-csi-driver/pull/137/files#diff-b337ddc97e6a08bd4b4ed602eaf20b1e3311ccba609376076fcf403ff045b016R675

cc @arahamad