add stop id, in case app wants to switch stops on notification tap

src/notifications/schedulers/ETANotificationScheduler.ts

@@ -48,6 +48,7 @@ export class ETANotificationScheduler {
       body: `Shuttle is approaching ${stop.name} in ${Math.ceil(eta.secondsRemaining / 60)} minutes.`,
       customKeys: {
         shuttleId,
+        stopId,
         systemId: this.interchangeSystemId,
       },
     }