Fix get_sample_data signature

desktop/libs/notebook/src/notebook/connectors/flink_sql.py

@@ -301,7 +301,8 @@ class FlinkSqlApi(Api):
     return response
 
   @query_error_handler
-  def get_sample_data(self, snippet, database=None, table=None, column=None, is_async=False, operation=None):
+  def get_sample_data(self, snippet, database=None, table=None, column=None, nested=False, is_async=False,
+                      operation=None):
     if operation == 'hello':
       snippet['statement'] = "SELECT 'Hello World!'"
     else: