[fix](variant) building index on the variant column is prohibited

[csun5285]

What problem does this PR solve?

this problem intro by #48461, should not remove this restriction.

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?

[eldenmoon]

LGTM

[github-actions]

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

[github-actions]

PR approved by anyone and no changes requested.

[csun5285]

run buildall

[doris-robot]

TPC-H: Total hot run time: 33742 ms

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/tpch-tools
Tpch sf100 test result on commit ca01c58931e5a6d04b3d20393c3e75d30913ac19, data reload: false

------ Round 1 ----------------------------------
q1	17622	5200	5137	5137
q2	1926	284	187	187
q3	10307	1276	726	726
q4	10251	981	516	516
q5	8324	2399	2282	2282
q6	211	159	131	131
q7	924	739	594	594
q8	9309	1296	1031	1031
q9	7129	5092	5093	5092
q10	6969	2380	1962	1962
q11	483	290	287	287
q12	369	348	222	222
q13	17779	3628	3025	3025
q14	241	237	214	214
q15	564	474	481	474
q16	425	423	375	375
q17	603	855	365	365
q18	7536	7130	7027	7027
q19	1393	947	562	562
q20	347	324	211	211
q21	3789	3255	2324	2324
q22	1080	1008	998	998
Total cold run time: 107581 ms
Total hot run time: 33742 ms

----- Round 2, with runtime_filter_mode=off -----
q1	5227	5094	5094	5094
q2	242	321	222	222
q3	2141	2687	2313	2313
q4	1317	1802	1338	1338
q5	4202	4559	4435	4435
q6	227	174	133	133
q7	2120	1923	1799	1799
q8	2695	2575	2518	2518
q9	7404	7401	7335	7335
q10	3140	3256	2894	2894
q11	561	531	510	510
q12	707	798	637	637
q13	3511	3827	3216	3216
q14	305	291	296	291
q15	522	511	486	486
q16	450	518	582	518
q17	1193	1584	1373	1373
q18	7909	7664	7510	7510
q19	823	845	988	845
q20	2027	2076	1908	1908
q21	4710	4333	4232	4232
q22	1100	1015	987	987
Total cold run time: 52533 ms
Total hot run time: 50594 ms

[doris-robot]

TPC-DS: Total hot run time: 184603 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 ca01c58931e5a6d04b3d20393c3e75d30913ac19, data reload: false

query1	998	378	428	378
query2	6530	1786	1739	1739
query3	6736	221	215	215
query4	25970	23703	23211	23211
query5	4360	619	463	463
query6	306	234	196	196
query7	4644	497	285	285
query8	275	235	217	217
query9	8607	2875	2886	2875
query10	471	337	282	282
query11	15813	15061	14729	14729
query12	167	111	118	111
query13	1662	554	421	421
query14	8597	5704	5670	5670
query15	222	190	171	171
query16	7333	647	487	487
query17	1210	720	594	594
query18	1994	423	322	322
query19	190	189	168	168
query20	135	120	118	118
query21	217	126	111	111
query22	4032	4105	4106	4105
query23	34283	33266	33335	33266
query24	8133	2299	2337	2299
query25	539	466	399	399
query26	1225	309	154	154
query27	2720	488	339	339
query28	4350	2246	2221	2221
query29	774	555	446	446
query30	288	224	196	196
query31	910	779	715	715
query32	90	74	76	74
query33	544	378	321	321
query34	793	841	499	499
query35	793	844	739	739
query36	983	992	910	910
query37	122	107	83	83
query38	4084	4019	3945	3945
query39	1456	1429	1422	1422
query40	221	130	111	111
query41	58	57	54	54
query42	120	108	110	108
query43	498	496	459	459
query44	1328	852	861	852
query45	172	169	166	166
query46	851	1006	637	637
query47	1736	1800	1746	1746
query48	395	415	313	313
query49	736	483	385	385
query50	641	696	394	394
query51	4088	4132	4124	4124
query52	113	110	109	109
query53	231	263	190	190
query54	596	619	526	526
query55	89	90	86	86
query56	317	339	304	304
query57	1164	1187	1118	1118
query58	275	268	269	268
query59	2558	2627	2509	2509
query60	343	342	329	329
query61	127	130	122	122
query62	786	729	679	679
query63	226	184	184	184
query64	4325	1011	694	694
query65	4264	4210	4215	4210
query66	1164	409	316	316
query67	15768	15398	15001	15001
query68	7966	908	568	568
query69	476	311	285	285
query70	1235	1109	1153	1109
query71	451	378	305	305
query72	5763	4793	4614	4614
query73	745	617	348	348
query74	9243	8974	9145	8974
query75	3785	3059	2619	2619
query76	3602	1132	714	714
query77	780	392	332	332
query78	9506	9658	8833	8833
query79	2426	808	612	612
query80	639	535	489	489
query81	478	251	227	227
query82	420	137	106	106
query83	279	312	238	238
query84	293	101	77	77
query85	787	374	350	350
query86	339	325	273	273
query87	4326	4299	4173	4173
query88	2898	2170	2178	2170
query89	378	317	289	289
query90	1903	225	218	218
query91	139	139	184	139
query92	93	72	68	68
query93	1151	962	638	638
query94	677	391	324	324
query95	385	314	303	303
query96	484	583	275	275
query97	2645	2692	2572	2572
query98	235	233	206	206
query99	1469	1429	1265	1265
Total cold run time: 271742 ms
Total hot run time: 184603 ms

[doris-robot]

ClickBench: Total hot run time: 32.73 s

machine: 'aliyun_ecs.c7a.8xlarge_32C64G'
scripts: https://github.com/apache/doris/tree/master/tools/clickbench-tools
ClickBench test result on commit ca01c58931e5a6d04b3d20393c3e75d30913ac19, data reload: false

query1	0.05	0.03	0.03
query2	0.08	0.04	0.04
query3	0.24	0.08	0.08
query4	1.61	0.10	0.11
query5	0.42	0.41	0.40
query6	1.16	0.62	0.65
query7	0.03	0.02	0.02
query8	0.05	0.03	0.03
query9	0.60	0.54	0.51
query10	0.57	0.57	0.57
query11	0.15	0.10	0.11
query12	0.15	0.11	0.11
query13	0.63	0.60	0.60
query14	0.80	0.82	0.82
query15	0.87	0.84	0.87
query16	0.38	0.41	0.39
query17	1.04	1.06	1.06
query18	0.22	0.19	0.19
query19	1.91	1.82	1.76
query20	0.02	0.01	0.01
query21	15.39	0.91	0.56
query22	0.76	1.20	0.72
query23	14.85	1.38	0.61
query24	6.38	1.11	1.01
query25	0.47	0.30	0.11
query26	0.59	0.17	0.12
query27	0.06	0.06	0.05
query28	10.39	0.99	0.43
query29	12.52	3.93	3.24
query30	3.10	3.01	3.02
query31	2.83	0.58	0.37
query32	3.24	0.55	0.47
query33	3.03	3.13	3.16
query34	16.00	5.44	4.88
query35	4.88	4.92	4.97
query36	0.68	0.50	0.49
query37	0.10	0.07	0.07
query38	0.05	0.05	0.04
query39	0.03	0.02	0.03
query40	0.18	0.14	0.15
query41	0.08	0.03	0.02
query42	0.04	0.03	0.02
query43	0.04	0.04	0.02
Total cold run time: 106.67 s
Total hot run time: 32.73 s

[zzzxl1993]

LGTM