Schemaless properties not supported in CEL template

[MisterMX]

Description

Observed Behavior:

When building an object in an RG that has an unstructured property marked with x-kubernetes-preserve-unknown-fields: true in the CRD schema, Kro fails the validation with an error:

failed to build resource 'vcluster': failed to extract CEL expressions from schema for resource vcluster: error getting field schema for path spec.forProvider.values.syncer: schema not found for field syncer

The template looks as follows:

spec:
  templates:
    - id: vcluster
      template:
        apiVersion: helm.crossplane.io/v1beta1
        kind: Release
        spec:
          forProvider:
            values: # <-- unstructured
              syncer:
                extraArgs:
                  - ${"--out-kube-config-server=https://" + schema.metadata.namespace + "." + schema.metadata.name + ".svc"}
                  - ${"--tls-san=" + schema.metadata.namespace + "." + schema.metadata.name + ".svc"}

In our case we are trying to create Release object from Crossplane provider-helm.

Expected Behavior:

The release should be created without any error messages, as any kind of property can be put at spec.forProvider.values.

Reproduction Steps (Please include ResourceGroup and Instances files):

• Install provider-helm CRDs
• Create RG with template above.

Versions:

• kro version: v0.1.0
• Kubernetes Version (kubectl version): v1.29.2 (kind)

Involved Controllers:
n.a.

Error Logs (if applicable)**:
n.a.

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