Kubernetes 1.34 introduced VolumeGroupSnapshot v1beta2 API and
deprecated v1beta1. Distributions running K8s 1.34+ (e.g. OpenShift
4.21+) have removed v1beta1 VGS CRDs entirely, breaking Velero's
VGS functionality on those clusters.
This change bumps external-snapshotter/client/v8 from v8.2.0 to
v8.4.0 and migrates all VGS API usage from v1beta1 to v1beta2.
The v1beta2 API is structurally compatible - the Spec-level types
(GroupSnapshotHandles, VolumeGroupSnapshotContentSource) are
unchanged. The Status-level change (VolumeSnapshotHandlePairList
replaced by VolumeSnapshotInfoList) does not affect Velero as it
does not directly consume that type.
Fixes#9694
Signed-off-by: Shubham Pampattiwar <spampatt@redhat.com>