[caissedepargne] We checked MILLEVIE insurances and we shouldn't

The flow is not the same for those (they are on natixis), so we don't
check if they are still opened, because it raises a BrowserUnavailable
(which is here for a good reason). The only way we do this check anyway
is to avoid bugs in the life insurance flow, which is not the same with
MILLEVIE.