Remove unused import (CI complaining)

Author: davidm-db

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/CatalystTypeConverters.scala

@@ -25,8 +25,6 @@ import java.time.{Duration, Instant, LocalDate, LocalDateTime, LocalTime, Period
 import java.util.{Map => JavaMap}
 import javax.annotation.Nullable
 
-import scala.language.existentials
-
 import org.apache.spark.SparkIllegalArgumentException
 import org.apache.spark.sql.Row
 import org.apache.spark.sql.catalyst.expressions._