Provide a configuration that allows velero backups to be successful with excluded pvc/datavolume

[30787]

Is your feature request related to a problem? Please describe:
Velero(kubervirt-velero plugin) backups of ocp vm fail when pvc/datavolume is excluded from backups.
Backup applications with own data mover prefer to use velero for metadata backup and backup/restore pvc/datavolume on its own.
Currently kubevirt-velero plugin fails velero backup when pvc is excluded from backup:
https://github.com/kubevirt/kubevirt-velero-plugin/blob/main/pkg/util/util.go

Describe the solution you'd like:
Request is to allow successful velero/kubevirt-velero backup when pvc/datavolume is excluded (ex-using some EXTERNAL_DM env variable or any other configurable approach)

Describe alternatives you've considered:
It will be great if you have any workaround for current behavior.

[alromeros]

Hey @30787, thanks for reporting this! We created a Jira story to track this issue https://issues.redhat.com/browse/CNV-47224. We'll start working on it as soon as possible.