Refs #30591 -- Fixed introspection of check and unique column constraints on MariaDB.

Unnamed unique and check columns constraints have the same name as
a column. Ensure uniqueness by using custom names.

Thanks Adnan Umer for the report.

tests/introspection/models.py

@@ -83,6 +83,7 @@ class Comment(models.Model):
 
 class CheckConstraintModel(models.Model):
     up_votes = models.PositiveIntegerField()
+    voting_number = models.PositiveIntegerField(unique=True)
 
     class Meta:
         required_db_features = {