[Bug](exec) Fix min max push agg error read char column

[HappenLee]

What problem does this PR solve?

mysql> set disable_nereids_rules='';
Query OK, 0 rows affected (0.00 sec)

mysql> select length(min(b)) from t;
+----------------+
| length(min(b)) |
+----------------+
|             10 |
+----------------+
1 row in set (0.01 sec)

mysql> set disable_nereids_rules=ELIMINATE_NOT_NULL;
Query OK, 0 rows affected (0.01 sec)

mysql> select length(min(b)) from t;
+----------------+
| length(min(b)) |
+----------------+
|              3 |
+----------------+
1 row in set (0.02 sec)

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

[hello-stephen]

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?

[HappenLee]

run buildall

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.

[doris-robot]

BE UT Coverage Report

Increment line coverage 0.00% (0/13) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	52.72% (19264/36541)
Line Coverage	36.11% (179040/495772)
Region Coverage	32.53% (138721/426383)
Branch Coverage	33.49% (60067/179345)

[doris-robot]

TPC-H: Total hot run time: 32080 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpch-tools
Tpch sf100 test result on commit 4bdebd09ac106e08fe66207ff6af9c9f80bbde89, data reload: false

------ Round 1 ----------------------------------
q1	17692	5294	5090	5090
q2	2058	325	185	185
q3	10196	1337	764	764
q4	10303	847	322	322
q5	8611	2148	1935	1935
q6	218	182	147	147
q7	860	744	616	616
q8	9273	1400	1122	1122
q9	5467	4840	4825	4825
q10	6860	1946	1546	1546
q11	518	300	275	275
q12	379	376	222	222
q13	17775	4052	3199	3199
q14	237	234	216	216
q15	928	811	833	811
q16	671	663	624	624
q17	800	774	511	511
q18	7611	6622	6691	6622
q19	1458	987	635	635
q20	379	339	221	221
q21	2659	2053	1914	1914
q22	351	317	278	278
Total cold run time: 105304 ms
Total hot run time: 32080 ms

----- Round 2, with runtime_filter_mode=off -----
q1	5450	5287	5325	5287
q2	250	352	246	246
q3	2169	2684	2283	2283
q4	1365	1745	1317	1317
q5	4295	4215	4586	4215
q6	253	202	154	154
q7	2084	2042	1759	1759
q8	2698	2484	2424	2424
q9	7582	7533	7502	7502
q10	2912	2996	2643	2643
q11	571	528	446	446
q12	656	743	621	621
q13	3953	4300	3738	3738
q14	299	317	285	285
q15	872	836	860	836
q16	688	737	675	675
q17	1229	1455	1446	1446
q18	8262	7913	8122	7913
q19	846	834	834	834
q20	2153	2158	1993	1993
q21	5163	4329	4044	4044
q22	567	589	522	522
Total cold run time: 54317 ms
Total hot run time: 51183 ms

[doris-robot]

ClickBench: Total hot run time: 28.28 s

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/clickbench-tools
ClickBench test result on commit 4bdebd09ac106e08fe66207ff6af9c9f80bbde89, data reload: false

query1	0.05	0.04	0.05
query2	0.10	0.04	0.04
query3	0.25	0.08	0.08
query4	1.61	0.11	0.11
query5	0.26	0.25	0.25
query6	1.17	0.68	0.67
query7	0.03	0.03	0.02
query8	0.05	0.04	0.04
query9	0.57	0.50	0.49
query10	0.55	0.53	0.54
query11	0.14	0.09	0.10
query12	0.14	0.10	0.10
query13	0.63	0.62	0.63
query14	1.06	1.03	1.05
query15	0.88	0.85	0.86
query16	0.39	0.37	0.39
query17	1.11	1.11	1.07
query18	0.22	0.21	0.21
query19	2.08	2.03	1.93
query20	0.02	0.02	0.01
query21	15.42	0.27	0.15
query22	5.06	0.06	0.05
query23	15.83	0.28	0.10
query24	2.40	0.36	0.41
query25	0.11	0.09	0.10
query26	0.14	0.13	0.13
query27	0.06	0.09	0.06
query28	5.02	1.15	0.97
query29	12.58	3.94	3.18
query30	0.28	0.13	0.11
query31	2.81	0.62	0.41
query32	3.24	0.59	0.50
query33	3.26	3.22	3.25
query34	15.92	5.41	4.74
query35	4.81	4.78	4.93
query36	0.65	0.50	0.49
query37	0.10	0.06	0.06
query38	0.08	0.04	0.04
query39	0.04	0.03	0.03
query40	0.18	0.17	0.16
query41	0.08	0.03	0.03
query42	0.04	0.03	0.03
query43	0.05	0.04	0.04
Total cold run time: 99.47 s
Total hot run time: 28.28 s

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 100.00% (13/13) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	73.17% (26210/35819)
Line Coverage	56.26% (278222/494539)
Region Coverage	53.93% (232265/430701)
Branch Coverage	55.67% (100234/180061)