TMSS-1124: also serialize SIPIdentifier into url and _id field

SAS/TMSS/backend/src/tmss/tmssapp/serializers/common.py

@@ -16,7 +16,7 @@ class FloatDurationField(serializers.FloatField):
         return value.total_seconds()
 
 class RelationalHyperlinkedModelSerializer(serializers.HyperlinkedModelSerializer):
-    _accepted_pk_names = ('id', 'name')
+    _accepted_pk_names = ('id', 'name', 'unique_identifier')
 
     def get_field_names(self, declared_fields, info):
         field_names = super().get_field_names(declared_fields, info)