[FIX] website_slides: Fix traceback when creating content in mobile

This commit fixes the traceback that happens when we try to create
a question from the survey form in mobile mode.

The problem was due to the context not being propagated
to the "add record" button that appears in mobile mode.
Therefore, as we use that context in our widget, it crashes.

The solution to this is to just use the normal tree view behavior
instead of our override when we are in a mobile environment.

LINKS

closes odoo/odoo#41143

Taskid: 2071342
Pr: #40694
X-original-commit: 0dc7d956
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>