[KYUUBI #1018] Set spark.sql.execution.topKSortFallbackThreshold to 10000

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### _Why are the changes needed?_
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To avoid performance issues in the topK scenario and close #1018 .

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [ ] [Run test](https://kyuubi.readthedocs.io/en/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #1054 from byyue/feature-1018.

Closes #1018

21de1fcb [Brian Yue] Set spark.sql.execution.topKSortFallbackThreshold to 10000

Authored-by: Brian Yue <code.byyue@gmail.com>
Signed-off-by: Kent Yao <yao@apache.org>

externals/kyuubi-spark-sql-engine/src/main/scala/org/apache/kyuubi/engine/spark/SparkSQLEngine.scala

@@ -96,6 +96,7 @@ object SparkSQLEngine extends Logging {
 
   def createSpark(): SparkSession = {
     val sparkConf = new SparkConf()
+    sparkConf.setIfMissing("spark.sql.execution.topKSortFallbackThreshold", "10000")
     sparkConf.setIfMissing("spark.sql.legacy.castComplexTypesToString.enabled", "true")
     sparkConf.setIfMissing("spark.master", "local")
     sparkConf.setIfMissing("spark.ui.port", "0")