fix: deleting empty planned work shifts

services/work_shifts_planning.py

@@ -73,6 +73,9 @@ class WorkShiftsPlanningService(BaseService):
                 created_at=datetime.now(),
             )
             self.session.add(work_shift)
+        else:
+            if len(positions) == 0:
+                await self.session.delete(work_shift)
             else:
                 work_shift.positions = positions