model: Rename OriginVisitUpdate to OriginVisitStatus
This also adapts the hypothesis strategies, using the plural form origin_visit_statuses. That plural form is acceptable because in our context, the statuses are countable.
Related to T2310 Related to [1]
To be able to update names in the current swh-storage!919 (closed) swh-storage!920 (closed) swh-storage!921 (closed) (they use origin visit update).
Test Plan
tox
Migrated from D3001 (view on Phabricator)