[FIX] web_editor: properly save multi-edited elements
[FIX] web_editor: properly save multi-edited elements

When an element is placed multiple times in a page, it is saved only
once. Unfortunately, when a view was divided in multiple editable
parts (XML branding), only one of those parts were saved.

ygol/odoo,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,ygol/odoo,ygol/odoo,Elico-Corp/odoo_OCB,ygol/odoo,ygol/odoo,Elico-Corp/odoo_OCB,ygol/odoo,ygol/odoo