Add UDF to Access Node Labels in Pixie Scripts

[srimaln91]

I have a use case where I need to capture the Rx and Tx bytes for each Kubernetes pod and export this data using OTEL exporter plugin. While Pixie provides good visibility into network metrics, I am currently unable to access node labels in Pixie scripts. This limitation makes it difficult to correlate pod network metrics with node-level metadata, which is critical for my use case.

It would be super helpful if we can have a User-Defined Function (UDF) to access node labels directly within Pixie scripts. This would allow enriching the captured metrics with node-level metadata (e.g., node roles, availability zones, or custom labels) and provide more context when exporting data via OTEL.