[FEATURE] Support extensions via Spark Conf

[noCharger]

Is your feature request related to a problem?

Right now spark extensions are override in flint https://github.com/opensearch-project/opensearch-spark/blob/43b14f4d857a4cfb0a1410[…]tion/src/main/scala/org/apache/spark/sql/FlintJobExecutor.scala, which limits the ability to use other extensions, including native ones, in Flint.

What solution would you like?

The proposed solution is to make the current set of Spark extensions a default one, rather than overriding all extensions. This would allow other extensions, including native Spark extensions, to be used in Flint.