PatreonAPI.fetchAccount() is called by both PatreonAPI.authenticate() and PatreonAPI.refreshPatreonAccount(), so this ensures the keychain is updated via both ways.
Rather than store both the current user’s Patreon account and all cached Friend Zone patrons in the same table, we now store Friend Zone patrons in the new ManagedPatron table. This avoids the need to distinguish between the two at runtime.