[FIX] web_editor: properly restore table rows on delete range

When deleting a selection in a table, we need to restore the cells the
browser removed or the table will be broken. We however failed to
restore the rows they belonged to when said rows were entirely contained
in the selection.

task-2930516

closes odoo/odoo#104831

Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>