lightning can import data with incorrect column number

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)
import data with incorrect column number
schema:
CREATE TABLE `sbtest1` (
`id` int(11) NOT NULL,
`name` varchar(220) DEFAULT NULL,
`price` int(11) NOT NULL,
`type` varchar(220) DEFAULT NULL,
PRIMARY KEY (`id`) /*T![clustered_index] CLUSTERED */,
UNIQUE KEY `some_index` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_bin;
data:
INSERT INTO `sbtest1` VALUES
(1,'name',100, 'name', 'tt'),
(2,'name',200,'name'),
(3,'name',300,'name');

### 2. What did you expect to see? (Required)
pre-check will report this error

### 3. What did you see instead (Required)
import success
mysql> select * from sbtest1;
+----+------+-------+------+
| id | name | price | type |
+----+------+-------+------+
| 1 | name | 100 | name |
| 2 | name | 200 | name |
| 3 | name | 300 | name |
+----+------+-------+------+

### 4. What is your TiDB version? (Required)

Release Version: v6.0.0
Git Commit Hash: 36a9810441ca0e496cbd22064af274b3be771081
Git Branch: heads/refs/tags/v6.0.0
Go Version: go1.18
UTC Build Time: 2022-03-31 10:28:59
Race Enabled: false