Live Search uses id=0 to display all search results to non-admin users
After clicking the Show All button for Live Search, results are shown in list view. Live search is currently hardcoded to always show the results on the site root (id=0), which is not accessible for non-admin users.
The old backend search solved this by always using the first webmount. This has its own issues, as described in #23190.
(issue imported from #M17045)