[FIX] website: provide favicon for pdf tabs

When opening the pdf at the end of an order Chrome tries to load
/favicon.ico which returns 404 before this patch. We provide the
favicon from the current website.

closes odoo/odoo#33746

Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>

addons/website/controllers/main.py

@@ -443,3 +443,8 @@ class WebsiteBinary(http.Controller):
             if unique:
                 kw['unique'] = unique
         return Binary().content_image(**kw)
+
+    @http.route(['/favicon.ico'], type='http', auth='public', website=True)
+    def favicon(self, **kw):
+        # when opening a pdf in chrome, chrome tries to open the default favicon url
+        return self.content_image(model='website', id=str(request.website.id), field='favicon', **kw)