[FIX] web: Fix access right issues on external layout prining

Purpose
=======

If the user doesn't have access to ir.ui.view (aka no admin or
website access rights), printing a report with a configured
external layout will lead to a traceback, as it's forbidden
for the use to read on the field "key" on the related ir.ui.view.

As we only want to retrieve the view key, this is safe to use
sudo at that point.

closes odoo/odoo#80510

Taskid: 2701251
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>