[SPARK-23927][SQL][FOLLOW-UP] Fix a build failure.

## What changes were proposed in this pull request?

This pr is a follow-up pr of #21155.
The #21155 removed unnecessary import at that time, but the import became necessary in another pr.

## How was this patch tested?

Existing tests.

Author: Takuya UESHIN <[email protected]>

Closes #21646 from ueshin/issues/SPARK-23927/fup1.

Author: ueshin

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/collectionOperations.scala

@@ -28,6 +28,7 @@ import org.apache.spark.sql.catalyst.expressions.codegen._
 import org.apache.spark.sql.catalyst.expressions.codegen.Block._
 import org.apache.spark.sql.catalyst.util._
 import org.apache.spark.sql.catalyst.util.DateTimeUtils._
+import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.types._
 import org.apache.spark.unsafe.Platform
 import org.apache.spark.unsafe.array.ByteArrayMethods