[FIX] website_slides: syntactically incorrect domain

- Go to a course of type 'Documentation', e.g. 'Trees ood and gardens'
- Search for any word

A traceback occurs since the domain is synctactically incorrect.

There is an extra `|` in the domain.

opw-2254210

closes odoo#51617

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/website_slides/controllers/main.py

@@ -350,7 +350,7 @@ def channel(self, channel, category=None, tag=None, page=1, slide_type=None, unc
 
         if search:
             domain += [
-                '|', '|', '|',
+                '|', '|',
                 ('name', 'ilike', search),
                 ('description', 'ilike', search),
                 ('html_content', 'ilike', search)]