[FIX] sale_timesheet: _get_timesheet_cost

A user must be set to get the right timesheet_cost

opw:684036

addons/sale_timesheet/models/sale_timesheet.py

@@ -73,7 +73,7 @@ class AccountAnalyticLine(models.Model):
             if result.get('amount'):
                 return result
             unit_amount = result.get('unit_amount', 0.0) or self.unit_amount
-            user_id = result.get('user_id') or self.user_id.id
+            user_id = result.get('user_id') or self.user_id.id or self._default_user()
             user = self.env['res.users'].browse([user_id])
             emp = self.env['hr.employee'].search([('user_id', '=', user_id)], limit=1)
             cost = emp and emp.timesheet_cost or 0.0