Adapt origin_get_latest_visit_status according to latest api change

Test Plan

tox (failing until swh.storage > 0.21 [1], swh.loader.core > 0.15 [2], swh.loader.git > 0.5 [3] are released)

• [1] swh-storage!1003 (closed)

• [2] swh-loader-core!410 (closed)

• [3] swh-loader-git!57 (closed)

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Migrated from D4988 (view on Phabricator)