Convert non-ascii slug field value to ascii for Blog Categories

AR: For now if slug field is not filled, by default slug value generates from name field using name value language. After that if you will try to update object error will occurs:

Steps to reproduce:

1. Choose Blog categories from admin panel -> Add blog category.
2. Fill name field with non-ascii text and fill all required fields.
3. Remove autofilled slug field value.
4. Save object.
5. Try to update object with autogenerated non-ascii slug field

ER: Always convert non-ascii slug value to ascii by default