Fixes for build output tables

- Only show "completed" builds in the "completed builds" table (should be obvious)
- Display "serial number" appropriately in build output allocation table

InvenTree/stock/serializers.py

@@ -64,6 +64,7 @@ class StockItemSerializerBrief(InvenTreeModelSerializer):
             'location',
             'location_name',
             'quantity',
+            'serial',
         ]