[#MDEV-28068] Change NATIONAL from utf8mb3 to utf8mb4

Data types NCHAR and NVARCHAR use CHARACTER SET utf8mb3.
With the general intent to switch from utf8mb3 to utf8mb4, this should also be fixed:

CREATE OR REPLACE TABLE t1 (a NCHAR);

SHOW CREATE TABLE t1;

+-------+-------------------------------------------------------------------------------------------------------------+

| Table | Create Table                                                                                                |

+-------+-------------------------------------------------------------------------------------------------------------+

| t1    | CREATE TABLE `t1` (

  `a` char(1) CHARACTER SET utf8mb3 DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

+-------+-------------------------------------------------------------------------------------------------------------+

[MDEV-28068] Change NATIONAL from utf8mb3 to utf8mb4 Created: 2022-03-15 Updated: 2024-02-06
Status:	Open
Project:	MariaDB Server
Component/s:	Character Sets
Fix Version/s:	10.11