fix: remove unused Set literal caught by spotless

Author: andygrove

spark/src/main/scala/org/apache/comet/serde/arrays.scala

@@ -816,19 +816,6 @@ trait ArraysBase {
 
 object CometArrayExists extends CometExpressionSerde[ArrayExists] {
 
-  private val supportedElementTypes: Set[Class[_]] = Set(
-    classOf[BooleanType],
-    classOf[ByteType],
-    classOf[ShortType],
-    classOf[IntegerType],
-    classOf[LongType],
-    classOf[FloatType],
-    classOf[DoubleType],
-    classOf[DecimalType],
-    classOf[DateType],
-    classOf[TimestampType],
-    classOf[StringType])
-
   private def isElementTypeSupported(dt: DataType): Boolean = dt match {
     case BooleanType | ByteType | ShortType | IntegerType | LongType | FloatType | DoubleType |
         _: DecimalType | DateType | TimestampType | StringType =>