Hide unvisited origins search option is not honored with elasticsearch backend

The search interface in swh-web has a only show origins visited at least once checkbox enabling to filter out origins that have been listed but not visited yet. The filter is implemented in the PostgreSQL storage of Software Heritage.

There is no such option in the elasticsearch backend which results in unvisited origins still displayed while the option is on (easy to spot, those are the ones with the always displayed "Checking" animation on their left).

In that case, the filter can be easily implemented on the frontend side.

---

Migrated from T2934 (view on Phabricator)