[FIX] website: Delete the current website

Steps to reproduce the bug:

- Delete the current website
- Go to homepage

Bug:

An error 500 was displayrd

opw:2381929

closes odoo/odoo#61849

X-original-commit: 0e7faad49ed78f5def56d9af90c383cbbfa42e9f
Signed-off-by: Simon Goffin (sig) <sig@openerp.com>