fix remove holiday bug incase adding and removing 1 holiday with a 1 …

…exisiting holiday

server/cshr/views/vacations.py

@@ -135,7 +135,7 @@ def post(self, request: Request) -> Response:
                 location=location, holiday_date__in=public_holidays
             ).values_list("id", flat=True)
 
-            if len(public_holidays) < len(balance[0].public_holidays.all()):
+            if len(public_holidays) <= len(balance[0].public_holidays.all()):
                 deleted_holidays = []
                 for holiday in balance[0].public_holidays.all():
                     if holiday.id not in public_holidays: