List a company's enabled currencies

Allows selectively disabling DRF uniqueness validation for ModelSerializers.

ModelSerializer runs unique field validation during is_valid(), even when the serializer is used only to deserialize or reference existing model data (i.e. with no intent to create or update an instance). This mixin enables callers to explicitly skip uniqueness checks for specific fields in those cases.

Usage: serializer = MySerializer( data=payload, skip_unique_validation_fields=('code',), )