UniqueConstraint violation_error_message as error response in drf

[AGM-90]

Example Model
class UniqueTest(BaseModel):
answer = models.ForeignKey(Answer, on_delete=models.CASCADE)
subject = models.ForeignKey(Subject, on_delete=models.CASCADE)
date = models.DateField()

class Meta:
    constraints = [
        models.UniqueConstraint(
            fields=["answer", "subject","date"],
            condition=Q(deleted_at=None),
            name="uniq_if_not_del_pjt_site_sub_mil",
            violation_error_message="test error message"
        )
    ]

Sample error response for violation
{
"non_field_errors": [
"The fields answer, subject, date must make a unique set."
]
}
Expected error response
{
"non_field_errors": [
"test error message"
]
}