[FIX] website: do not reuse an existing view key for a page key

When generating a new page key, it was only made sure to not match
existing page keys. This leads to COW happening on existing views if the
key already existed in a view.

This commit ensures that new page keys are not existing view keys
either.

Steps to reproduce:
- Create a page named "snippets".

=> Notification was shown indicating that `website.snippets` is private.

task-3328827

closes odoo/odoo#123693

X-original-commit: e7ef9f0bfc59a468c9f883561c371367cc06c1b7
Signed-off-by: Romain Derie (rde) <rde@odoo.com>
Signed-off-by: Benoit Socias (bso) <bso@odoo.com>

addons/website/models/website.py

@@ -817,7 +817,7 @@ class Website(models.Model):
         website_id = self.env.context.get('website_id', False)
         if website_id:
             domain_static = [('website_id', 'in', (False, website_id))]
-        while self.env['website.page'].with_context(active_test=False).sudo().search([('key', '=', key_copy)] + domain_static):
+        while self.env['ir.ui.view'].with_context(active_test=False).sudo().search([('key', '=', key_copy)] + domain_static):
             inc += 1
             key_copy = string + (inc and "-%s" % inc or "")
         return key_copy