fix: place desktop bell before the secondary-nav cluster

INSERT_BEFORE the desktopSecondaryLinks widget rather than the auth
menu so the bell renders to the left of any secondary nav links
(e.g. the help button from frontend-base#245) instead of between
those links and the user avatar dropdown.

Mobile is left as-is — mobileRight has no secondary-nav cluster to
position relative to (just bell + auth menu), so INSERT_BEFORE the
mobile auth menu remains correct.

Refs openedx/frontend-base#245

Author: brian-smith-tcril

src/slots.tsx

@@ -7,7 +7,7 @@ const slots: SlotOperation[] = [
     slotId: 'org.openedx.frontend.slot.header.desktopRight.v1',
     id: `${appId}.widget.notificationsBell.desktop.v1`,
     op: WidgetOperationTypes.INSERT_BEFORE,
-    relatedId: 'org.openedx.frontend.widget.header.desktopAuthenticatedMenu.v1',
+    relatedId: 'org.openedx.frontend.widget.header.desktopSecondaryLinks.v1',
     element: <NotificationsTray />,
     condition: { authenticated: true },
   },