fix: Fix the JSON schema of JsonConfigOverrides

[siegfriedweber]

Description

Fix the JSON schema of JsonConfigOverrides

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added

[adwk67]

jsonPatch: array (real RFC-6902), previously rejected at admission, is now admitted + reconciled:

$ kubectl apply --dry-run=server -n render-diff -f - <<'EOF'
apiVersion: opa.stackable.tech/v1alpha2
kind: OpaCluster
metadata:
  name: jsonpatch-repro
spec:
  image:
    productVersion: "1.16.2"
  servers:
    configOverrides:
      config.json:
        jsonPatch:
          - op: add
            path: /default_decision
            value: allow
    roleGroups:
      default: {}
EOF
opacluster.opa.stackable.tech/jsonpatch-repro created (server dry run)