Fix audit scanner test

[kravciak]

Current test is failing because of couple test bugs: https://github.com/kubewarden/kubewarden-controller/actions/runs/9200131811/job/25315596449

• empty does not check that keys are not present, this code passes only because of missing -e

  jq '[.results[] | select(.policy == "clusterwide-psa-label-enforcer-policy")] | empty'

• kubectl returns no results so jq always fail because of no input (if tested cluster is clean)

  retry "kubectl get --ignore-not-found policyreport -A -o json | jq -e '.items[] | empty'"

• created helper methods to clean up checks
• rewrote jq expressions