[FEATURE] Expose PPL Parser Errors Instead of Swallowing Them

[noCharger]

Is your feature request related to a problem?

Currently, when the PPL parser fails to parse a query, the FlintSparkPPLParser class swallows the PPL parser error and falls back to the Flint SQL parser. This behavior can lead to confusing error messages for users, as the actual PPL parser error is replaced by a different error from the SQL parser.

opensearch-spark/ppl-spark-integration/src/main/scala/org/opensearch/flint/spark/ppl/FlintSparkPPLParser.scala

Lines 54 to 68 in beac01a

	override def parsePlan(sqlText: String): LogicalPlan = {
	try {
	// if successful build ppl logical plan and translate to catalyst logical plan
	val context = new CatalystPlanContext
	planTrnasormer.visit(plan(pplParser, sqlText, false), context)
	context.getPlan
	} catch {
	// Fall back to Spark parse plan logic if flint cannot parse
	case _: ParseException | _: SyntaxCheckException => sparkParser.parsePlan(sqlText)
	}
	}
	override def parseExpression(sqlText: String): Expression = sparkParser.parseExpression(sqlText)
	override def parseTableIdentifier(sqlText: String): TableIdentifier =

What solution would you like?

1. Modify the FlintSparkPPLParser class to accept a SparkSession object in its constructor:

 class FlintSparkPPLParser(sparkParser: ParserInterface, sparkSession: SparkSession) extends ParserInterface { // ...} 

2. Update the FlintPPLSparkExtensions class to pass the SparkSession object to the FlintSparkPPLParser constructor:

class FlintPPLSparkExtensions extends (SparkSessionExtensions => Unit) {
    override def apply(extensions: SparkSessionExtensions): Unit = {
        extensions.injectParser { (spark, parser) =>
            new FlintSparkPPLParser(parser, spark)
        }
    }
}

Instead of swallowing the PPL parser errors, throw the exception directly if the language type is specified as PPL (from spark conf) in the parsePlan method of FlintSparkPPLParser.

What alternatives have you considered?
An alternative approach would be to pass the PPL exception along with the CatalystPlanContext and determine which exception to throw from downstream components. However, this approach might introduce additional complexity and make the code harder to maintain and understand.