Allow stocktake quantity to be zero (#5644)

- Backport of https://github.com/inventree/InvenTree/pull/5627/

Co-authored-by: Oliver Lippert <oliver@allesit.de>

InvenTree/part/tasks.py

@@ -314,10 +314,6 @@ def generate_stocktake_report(**kwargs):
         # Create a new stocktake for this part (do not commit, this will take place later on)
         stocktake = perform_stocktake(p, user, commit=False)
 
-        if stocktake.quantity == 0:
-            # Skip rows with zero total quantity
-            continue
-
         total_parts += 1
 
         stocktake_instances.append(stocktake)

InvenTree/part/test_api.py

@@ -2966,7 +2966,7 @@ class PartStocktakeTest(InvenTreeAPITestCase):
 
         data = response.data[0]
 
-        self.assertEqual(data['part_count'], 8)
+        self.assertEqual(data['part_count'], 14)
         self.assertEqual(data['user'], None)
         self.assertTrue(data['report'].endswith('.csv'))