loader: Read snapshot out of the last origin visit status
Preparatory work to drop unused fields in OriginVisit.
Related to T2310
Test Plan
tox
Migrated from D3307 (view on Phabricator)
Staging instance, all changes can be removed at any time
Preparatory work to drop unused fields in OriginVisit.
Related to T2310
tox
Migrated from D3307 (view on Phabricator)