Insert "n" length unicode string to a column with data type "varchar(n)" cause data too long error.

[kchenzhi]

Steps to reproduce the behavior (Required)

1. CREATE TABLE varchar_test(name varchar(5))
2. INSERT INTO varchar_test values('一二三四五')

Expected behavior (Required)

Insert operation successed.

Real behavior (Required)

Error: String '一二三四五'(length=15) is too long. The max length of 'name' is 5

StarRocks version (Required)

3.3.4-56bcf6f

This operation execute normally in Mysql or PG.
These database document describe that columns with datatype varchar(n) can store strings up to n characters (not bytes) in length. https://www.postgresql.org/docs/current/datatype-character.html

When I query the metadata of table varchar_test in starrocks, it shows similar information:

But the real behavior is different.

By the way, this issue also affect MVs load data from external JDBC catalog.
When datas with unicode characters too long, the data will ignore by the loading task.