Add ScalarFunction for JSON_EXTRACT_SCALAR

[Jackie-Jiang]

Add ScalarFunction counterpart of JSON_EXTRACT_SCALAR

[sanchay9]

Hi @Jackie-Jiang, would like to try this, can you assign this to me

[Jayesh-Asrani]

I think there already exist a few similar functions for Ingestion Transformation e.g. : https://docs.pinot.apache.org/functions-1/jsonpath#signature

[manikBS]

Hi @Jackie-Jiang,
I would like to work on this issue. This will be my first contribution to Apache Pinot, and I’m eager to continue contributing more in the future. Could you please assign this issue (and any related ones) to me?

Here is the corresponding PR: #16910
It would be great if you could review the PR and share your suggestions for improvements.