Previously handleRouteSubmit required both fields and returned silently
when only one was filled. Angular's
OnlineBoardUrlBuilderService.getRoutePageUrl switches on which side is
populated, routing to /onlineboard/departure/{dep}-{date} or
/onlineboard/arrival/{arr}-{date} for one-sided searches. React now
mirrors the same branch and only no-ops when neither side is filled
(matching Angular's `if (!departure && !arrival) return;` in
OnlineBoardFilterService.toRoutePage).
gnezim
37ebda8455