[bugfix](zonemap string) datetimev2 should always using scale 6 to produce string

[yiguolei]

What problem does this PR solve?

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[Thearas]

Thank you for your contribution to Apache Doris.
Don't know what should be done next? See How to process your PR.

Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[yiguolei]

run buildall

[doris-robot]

TPC-H: Total hot run time: 26757 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpch-tools
Tpch sf100 test result on commit e3f0112f1a1672e57f59512c9330fde7e3c76703, data reload: false

------ Round 1 ----------------------------------
orders	Doris	NULL	NULL	0	0	0	NULL	0	NULL	NULL	2023-12-26 18:27:23	2023-12-26 18:42:55	NULL	utf-8	NULL	NULL	
============================================
q1	17624	4389	4281	4281
q2	q3	10659	788	511	511
q4	4683	359	248	248
q5	7560	1202	1024	1024
q6	183	177	149	149
q7	785	839	665	665
q8	9314	1483	1338	1338
q9	4879	4755	4662	4662
q10	6253	1936	1651	1651
q11	455	271	245	245
q12	723	580	463	463
q13	18045	2982	2138	2138
q14	230	234	213	213
q15	q16	725	736	660	660
q17	726	828	451	451
q18	6021	5333	5424	5333
q19	1123	966	624	624
q20	527	505	376	376
q21	4381	1851	1404	1404
q22	363	495	321	321
Total cold run time: 95259 ms
Total hot run time: 26757 ms

----- Round 2, with runtime_filter_mode=off -----
orders	Doris	NULL	NULL	150000000	42	6422171781	NULL	22778155	NULL	NULL	2023-12-26 18:27:23	2023-12-26 18:42:55	NULL	utf-8	NULL	NULL	
============================================
q1	4817	4586	4631	4586
q2	q3	3887	4312	3825	3825
q4	905	1205	772	772
q5	4083	4387	4344	4344
q6	198	176	140	140
q7	1811	1696	1519	1519
q8	2519	2726	2549	2549
q9	7677	7482	7438	7438
q10	3803	4004	3588	3588
q11	504	431	409	409
q12	487	584	442	442
q13	2758	3097	2635	2635
q14	282	304	273	273
q15	q16	747	755	721	721
q17	1154	1343	1346	1343
q18	7278	6812	6573	6573
q19	899	1019	938	938
q20	2157	2161	1996	1996
q21	3956	3542	3367	3367
q22	463	425	378	378
Total cold run time: 50385 ms
Total hot run time: 47836 ms

[doris-robot]

TPC-DS: Total hot run time: 168077 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpcds-tools
TPC-DS sf100 test result on commit e3f0112f1a1672e57f59512c9330fde7e3c76703, data reload: false

query5	4335	655	509	509
query6	335	231	207	207
query7	4204	498	275	275
query8	352	248	234	234
query9	8711	2740	2701	2701
query10	496	375	330	330
query11	7013	5097	4866	4866
query12	184	130	125	125
query13	1280	484	345	345
query14	5778	3684	3473	3473
query14_1	2815	2814	2826	2814
query15	206	190	173	173
query16	969	451	433	433
query17	858	710	629	629
query18	2449	443	343	343
query19	224	211	200	200
query20	133	123	127	123
query21	211	126	105	105
query22	13253	13905	14625	13905
query23	16173	16124	15711	15711
query23_1	15708	15573	15328	15328
query24	7127	1697	1237	1237
query24_1	1250	1219	1242	1219
query25	552	475	418	418
query26	1236	271	150	150
query27	2770	494	300	300
query28	4526	1840	1837	1837
query29	831	573	471	471
query30	292	225	191	191
query31	997	937	867	867
query32	83	69	73	69
query33	509	338	287	287
query34	916	928	525	525
query35	647	680	599	599
query36	1081	1096	959	959
query37	134	96	82	82
query38	2943	2901	2847	2847
query39	858	847	806	806
query39_1	796	786	815	786
query40	227	155	139	139
query41	61	59	62	59
query42	263	260	258	258
query43	249	251	220	220
query44	
query45	202	189	185	185
query46	914	1033	641	641
query47	2101	2561	2087	2087
query48	319	326	229	229
query49	647	465	377	377
query50	734	295	218	218
query51	4048	4073	3984	3984
query52	268	266	253	253
query53	299	365	289	289
query54	304	269	264	264
query55	93	88	82	82
query56	322	313	305	305
query57	1828	1826	1718	1718
query58	282	276	272	272
query59	2821	2943	2752	2752
query60	347	346	315	315
query61	157	156	153	153
query62	631	596	537	537
query63	318	284	274	274
query64	4986	1278	1017	1017
query65	
query66	1460	482	348	348
query67	24268	24234	24107	24107
query68	
query69	408	325	292	292
query70	994	962	969	962
query71	358	315	287	287
query72	3014	2891	2657	2657
query73	558	570	329	329
query74	9655	9563	9381	9381
query75	2956	2799	2488	2488
query76	2292	1134	724	724
query77	374	370	306	306
query78	10962	11116	10433	10433
query79	1150	797	576	576
query80	1294	646	545	545
query81	536	268	223	223
query82	1374	160	125	125
query83	381	267	247	247
query84	298	129	106	106
query85	927	505	450	450
query86	393	322	321	321
query87	3142	3107	3024	3024
query88	3611	2667	2651	2651
query89	452	380	346	346
query90	1872	182	170	170
query91	170	176	141	141
query92	85	75	70	70
query93	960	891	501	501
query94	563	321	315	315
query95	595	404	330	330
query96	651	570	231	231
query97	2528	2503	2395	2395
query98	255	219	222	219
query99	1024	990	916	916
Total cold run time: 248566 ms
Total hot run time: 168077 ms

[hello-stephen]

BE UT Coverage Report

Increment line coverage 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	52.70% (19782/37535)
Line Coverage	36.22% (184682/509907)
Region Coverage	32.48% (143021/440292)
Branch Coverage	33.66% (62541/185811)

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 100% (0/0) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	73.26% (26914/36738)
Line Coverage	56.74% (288326/508193)
Region Coverage	54.06% (240207/444338)
Branch Coverage	55.79% (103937/186293)