test: fix shell syntax error in clone-cluster template

Use env var instead of JMESPath expression in shell script.

Author: sfc-gh-jmckulka

testing/chainsaw/e2e/pgbackrest-restore/templates/clone-cluster.yaml

@@ -39,10 +39,13 @@ spec:
         duration: 5s
 
     - description: Check PVC provisioning status early
+      env:
+        - name: CLUSTER_NAME
+          value: ($name)
       script:
         content: |
-          echo "=== PVCs for ($name) ==="
-          kubectl get pvc -l postgres-operator.crunchydata.com/cluster=($name) -o wide || true
+          echo "=== PVCs for ${CLUSTER_NAME} ==="
+          kubectl get pvc -l postgres-operator.crunchydata.com/cluster=${CLUSTER_NAME} -o wide || true
           echo ""
           echo "=== All PVC Events ==="
           kubectl get events --field-selector involvedObject.kind=PersistentVolumeClaim -o wide | tail -20 || true