Breadcrumbs: use BOARD.TITLE, drop flight-number leaf

Angular's details breadcrumb trail is just 'Главная / Онлайн-Табло'
(BOARD.TITLE with capital Т) — the flight number itself is NOT a
breadcrumb entry. React was using the lowercase 'Онлайн-табло'
translation and appending 'SU 6272'. Align both the leaf text and the
list depth with Angular.

src/features/online-board/components/OnlineBoardDetailsPage.tsx

@@ -461,11 +461,12 @@ export const OnlineBoardDetailsPage: FC<OnlineBoardDetailsPageProps> = ({
   );
 
   const onlineboardHref = `/${locale}/onlineboard`;
+  // Angular uses the 'Онлайн-Табло' title (BOARD.TITLE) as the sole
+  // breadcrumb leaf — the flight number itself is NOT a breadcrumb entry.
+  const rootBreadcrumbLabel = t("BOARD.TITLE");
   const commonLayoutProps = {
     headerLeft: <DetailsBackButton locale={locale} />,
-    breadcrumbs: [
-      { label: t("BREADCRUMBS.ONLINEBOARD"), url: onlineboardHref },
-    ],
+    breadcrumbs: [{ label: rootBreadcrumbLabel, url: onlineboardHref }],
   };
 
   if (loading) {
@@ -516,10 +517,7 @@ export const OnlineBoardDetailsPage: FC<OnlineBoardDetailsPageProps> = ({
       <PageLayout
         headerLeft={<DetailsBackButton locale={locale} />}
         title={<h1 className="flight-details__flight-number">{pageTitle}</h1>}
-        breadcrumbs={[
-          { label: t("BREADCRUMBS.ONLINEBOARD"), url: onlineboardHref },
-          { label: flightNumber },
-        ]}
+        breadcrumbs={[{ label: rootBreadcrumbLabel, url: onlineboardHref }]}
         contentLeft={
           <FlightsMiniList
             flights={miniListFlights}