fix: Show S3 snapshots in ETCDMachineSnapshot status

[yiannistri]

What this PR does / why we need it:

The ETCDSnapshotFile resources that represent S3 snapshots in downstream clusters, do not have a node/machine name in their spec, as it's always set to S3. Local snapshots on the other hand have a node name that captures the name of the RKE2 CP node that the snapshot was captured on. Because of the way that the check for the node name was done before, we would exclude any S3 snapshots from appearing in status. By moving that part of the code further down, that no longer happens.

S3 snapshot

 kubectl --kubeconfig rke2.kubeconfig get etcdsnapshotfiles.k3s.cattle.io s3-etcd-snapshot-rke2-control-plane-dxqfw-1740039301-bb47e5 -o yaml
apiVersion: k3s.cattle.io/v1
kind: ETCDSnapshotFile
metadata:
  annotations:
    etcd.rke2.cattle.io/snapshot-token-hash: ff2427fc2541
  creationTimestamp: "2025-02-20T08:15:05Z"
  finalizers:
  - wrangler.cattle.io/managed-etcd-snapshots-controller
  generation: 1
  labels:
    etcd.rke2.cattle.io/snapshot-storage-node: s3
  name: s3-etcd-snapshot-rke2-control-plane-dxqfw-1740039301-bb47e5
  resourceVersion: "4723"
  uid: d313efac-5a22-4a93-ac58-b65964b15f5e
spec:
  location: s3://etcd-snapshots-2025/etcd-snapshot-rke2-control-plane-dxqfw-1740039301
  nodeName: s3
  s3:
    bucket: etcd-snapshots-2025
    endpoint: s3.amazonaws.com
    region: eu-west-1
    skipSSLVerify: true
  snapshotName: etcd-snapshot-rke2-control-plane-dxqfw-1740039301
status:
  creationTime: "2025-02-20T08:15:01Z"
  readyToUse: true
  size: "13803552

Local snapshot

kubectl --kubeconfig rke2.kubeconfig get etcdsnapshotfiles.k3s.cattle.io local-etcd-snapshot-rke2-control-plane-dxqfw-1740039301-c4212e -o yaml
apiVersion: k3s.cattle.io/v1
kind: ETCDSnapshotFile
metadata:
  annotations:
    etcd.rke2.cattle.io/snapshot-token-hash: ff2427fc2541
  creationTimestamp: "2025-02-20T08:15:01Z"
  finalizers:
  - wrangler.cattle.io/managed-etcd-snapshots-controller
  generation: 1
  labels:
    etcd.rke2.cattle.io/snapshot-storage-node: rke2-control-plane-dxqfw
  name: local-etcd-snapshot-rke2-control-plane-dxqfw-1740039301-c4212e
  resourceVersion: "4706"
  uid: 56b3ef9c-aed6-431d-a70a-5727c0dbb71d
spec:
  location: file:///var/lib/rancher/rke2/server/db/snapshots/etcd-snapshot-rke2-control-plane-dxqfw-1740039301
  nodeName: rke2-control-plane-dxqfw
  snapshotName: etcd-snapshot-rke2-control-plane-dxqfw-1740039301
status:
  creationTime: "2025-02-20T08:15:01Z"
  readyToUse: true
  size: "13803552"

Special notes for your reviewer:

Checklist:

• squashed commits into logical changes
• includes documentation
• adds unit tests
• adds or updates e2e tests