add rancher statistics to inventory entries list - fix bug of login for empty string device identity

apps/warehouse/pos/api/v1/serializers.py

@@ -1,3 +1,4 @@
+from apps.herd.services.services import get_rancher_statistics, rancher_quota_weight
 from apps.pos_device.pos.api.v1.serializers.device import DeviceSerializer
 from apps.herd.pos.api.v1.serializers import RancherSerializer
 from apps.warehouse.exceptions import (
@@ -47,6 +48,14 @@ class InventoryEntrySerializer(serializers.ModelSerializer):
                 'id': instance.distribution.quota.product.id,
             }
 
+        # rancher herd & live stock statistics
+        representation['rancher_statistics'] = get_rancher_statistics(self.context['rancher'])
+
+        # rancher live stock statistics by inventory entry
+        representation['rancher_quota_weight_statistics'] = rancher_quota_weight(
+            self.context['rancher'], instance
+        )
+
         return representation