[KYUUBI #3568] [Bug] [Doris Engine] Fix return decimal, date, timestamp using string

### _Why are the changes needed?_

close #3568 (comment)

### _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.apache.org/docs/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #3569 from zhaomin1423/fix_doris_type.

Closes #3568

f83cc48 [Min Zhao] fix style
d044747 [Min Zhao] [KYUUBI #3568] [Bug] [Doris Engine] Fix return decimal, date, timestamp using string

Authored-by: Min Zhao <zhaomin1423@163.com>
Signed-off-by: Kent Yao <yao@apache.org>
(cherry picked from commit 5ec0c86)
Signed-off-by: Kent Yao <yao@apache.org>

Author: zhaomin1423

externals/kyuubi-jdbc-engine/src/main/scala/org/apache/kyuubi/engine/jdbc/doris/DorisSchemaHelper.scala

@@ -44,13 +44,13 @@ class DorisSchemaHelper extends SchemaHelper {
       TTypeId.STRING_TYPE
 
     case Types.DATE =>
-      TTypeId.STRING_TYPE
+      TTypeId.DATE_TYPE
 
     case Types.TIMESTAMP =>
-      TTypeId.STRING_TYPE
+      TTypeId.TIMESTAMP_TYPE
 
     case Types.DECIMAL =>
-      TTypeId.STRING_TYPE
+      TTypeId.DECIMAL_TYPE
 
     // TODO add more type support
     case _ =>

externals/kyuubi-jdbc-engine/src/test/scala/org/apache/kyuubi/engine/jdbc/doris/StatementSuite.scala

@@ -16,6 +16,8 @@
  */
 package org.apache.kyuubi.engine.jdbc.doris
 
+import java.sql.{Date, Timestamp}
+
 import org.apache.kyuubi.operation.HiveJDBCTestHelper
 
 class StatementSuite extends WithDorisEngine with HiveJDBCTestHelper {
@@ -77,9 +79,9 @@ class StatementSuite extends WithDorisEngine with HiveJDBCTestHelper {
         assert(resultSet1.getObject(4) == 4)
         assert(resultSet1.getObject(5) == 5)
         assert(resultSet1.getObject(6) == "6")
-        assert(resultSet1.getObject(7) == "7.7")
-        assert(resultSet1.getObject(8) == "2022-05-08")
-        assert(resultSet1.getObject(9) == "2022-05-08 17:47:45")
+        assert(resultSet1.getObject(7) == new java.math.BigDecimal("7.7"))
+        assert(resultSet1.getObject(8) == Date.valueOf("2022-05-08"))
+        assert(resultSet1.getObject(9) == Timestamp.valueOf("2022-05-08 17:47:45"))
         assert(resultSet1.getObject(10) == "a")
         assert(resultSet1.getObject(11) == "Hello")
         assert(resultSet1.getObject(12) == "Hello, Kyuubi")