Before this commit, it was not possible to install website_forum if the 'Main Frontent Layout' had been COW'd. When loading Forum Layout view which is a primary child view, it would crash during view validation, not finding the element to xpath. Triggering COW instead of copying fix the issue. opw-2036119 closes odoo/odoo#35138 Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>