Use spark.sessionState.artifactManager instead of spark.artifactManager

Avoids needing ClassicConversions import in DDLSuite.

Co-authored-by: Isaac

Author: zhengruifeng

sql/core/src/test/scala/org/apache/spark/sql/execution/command/DDLSuite.scala

@@ -32,7 +32,6 @@ import org.apache.spark.sql.catalyst.analysis.TempTableAlreadyExistsException
 import org.apache.spark.sql.catalyst.catalog._
 import org.apache.spark.sql.catalyst.catalog.CatalogTypes.TablePartitionSpec
 import org.apache.spark.sql.catalyst.parser.ParseException
-import org.apache.spark.sql.classic.ClassicConversions._
 import org.apache.spark.sql.connector.catalog.CatalogManager
 import org.apache.spark.sql.connector.catalog.CatalogManager.SESSION_CATALOG_NAME
 import org.apache.spark.sql.connector.catalog.SupportsNamespaces.PROP_OWNER
@@ -2235,7 +2234,7 @@ abstract class DDLSuite extends QueryTest with DDLSuiteBase {
     // TODO(SPARK-50244): ADD JAR is inside `sql()` thus isolated. This will break an existing Hive
     //  use case (one session adds JARs and another session uses them). After we sort out the Hive
     //  isolation issue we will decide if the next assert should be wrapped inside `withResources`.
-    spark.artifactManager.withResources {
+    spark.sessionState.artifactManager.withResources {
       assert(new File(SparkFiles.get(s"${directoryToAdd.getName}/${testFile.getName}")).exists())
     }
   }