Allow unit of measure ratio change when there are no product currently reserved or in stock using this unit of measure. opw-2455914 closes odoo/odoo#67827 X-original-commit: d78238843ea8933b62d340d1b231a12e94bbf957 Signed-off-by: Arnold Moyaux <amoyaux@users.noreply.github.com> Signed-off-by: Jean-François Aubert <ajf-odoo@users.noreply.github.com>