Since 2515482d5a70, the duration expected of a workorder was always set to the real duration at the validation of the workorder. This commit ensure the duration expected is left unchanged even if the date_planned_finished is updated. closes odoo/odoo#108233 X-original-commit: 46e1ae4d9918de1aaf6b4a7565dba422b03fcb36 Signed-off-by: William Henrotin (whe) <whe@odoo.com>