Reverse migrations fail with mysql / mariadb with sql_safe_updates set to 1

[Divick]

For one of the migrations when I tried deleting, it generates something like the following:

DELETE FROM `django_migrations` WHERE (`django_migrations`.`app` = 'cards' AND `django_migrations`.`name` = '0023_user_pin_code');

The problem is that django_migrations.name column is not indexed nor is django_migrations.app column, which leads to sql_safe_update error:

MySQLdb.OperationalError: (1175, 'You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column')

I think django_migrations.name column can be made unique to solve this issue.

The version of Django that I am using is 4.0.10.

[Mariusz Felisiak]

Duplicate of #30490.