Fix unit test

Author: zwangsheng

kyuubi-server/src/main/scala/org/apache/kyuubi/server/metadata/api/Metadata.scala

@@ -78,7 +78,7 @@ case class Metadata(
     engineState: String = null,
     engineError: Option[String] = None,
     endTime: Long = 0L,
-    priority: Option[Int] = None,
+    priority: Int = 10,
     peerInstanceClosed: Boolean = false) {
   def appMgrInfo: ApplicationManagerInfo = {
     ApplicationManagerInfo(

kyuubi-server/src/main/scala/org/apache/kyuubi/session/KyuubiBatchSession.scala

@@ -179,7 +179,7 @@ class KyuubiBatchSession(
           createTime = createTime,
           engineType = batchType,
           clusterManager = batchJobSubmissionOp.builder.clusterManager(),
-          priority = conf.get(KYUUBI_BATCH_PRIORITY).map(_.toInt))
+          priority = conf.get(KYUUBI_BATCH_PRIORITY).map(_.toInt).getOrElse(10))
 
         // there is a chance that operation failed w/ duplicated key error
         sessionManager.insertMetadata(newMetadata)

kyuubi-server/src/main/scala/org/apache/kyuubi/session/KyuubiSessionManager.scala

@@ -238,7 +238,7 @@ class KyuubiSessionManager private (name: String) extends SessionManager(name) {
       requestArgs = batchRequest.getArgs.asScala.toSeq,
       createTime = System.currentTimeMillis(),
       engineType = batchRequest.getBatchType,
-      priority = conf.get(KYUUBI_BATCH_PRIORITY).map(_.toInt))
+      priority = conf.get(KYUUBI_BATCH_PRIORITY).map(_.toInt).getOrElse(10))
 
     // there is a chance that operation failed w/ duplicated key error
     metadataManager.foreach(_.insertMetadata(metadata, asyncRetryOnError = false))