Update volume policy check to use 'custom' action after upstream velero changes

[shubham-pampattiwar]

Summary

The kubevirt datamover plugin currently checks for snapshot volume policy action to determine if a VM should be backed up via the kubevirt datamover.

Once upstream Velero changes are merged (adding support for custom volume policy actions), this should be updated to check for custom action type and inspect the action parameters map to verify it's for kubevirt (not some other custom action).

Related

• Upstream discussion: Design for virt qcow2 datamover openshift/oadp-operator#2037
• PR Add VirtualMachine BackupItemAction plugin for kubevirt datamover #2 comment: Add VirtualMachine BackupItemAction plugin for kubevirt datamover #2 (comment)

TODO

• Update checkVolumePolicies to check for custom action type
• Inspect action parameters map to verify kubevirt-specific action
• Update related constants in common/types.go