Fix SIRI ET ExtraJourney trips not appearing in departure/arrival boards

[t2gran]

Summary

SIRI ET ExtraJourney trips (real-time added trips) were successfully created and could be queried directly by trip ID, but they did not appear in departure/arrival board queries at stops. This PR fixes the issue by ensuring ExtraJourney patterns are properly indexed for stop-based queries.

THIS PR NEEDS TO BE DISCUSSED - I DISCUSSED THIS WITH VINCENT AND WE ARE NOT 100% SURE THIS IS THE RIGHT FIX.

Issue

Fixes #7008

Root Cause

The AddedTripBuilder created TripPattern objects for ExtraJourneys without setting the createdByRealtimeUpdater flag. This caused TimetableSnapshot.addPatternToIndex() to skip indexing these patterns in the patternsForStop multimap, which is used by departure board queries.

Code Flow

1. Departure board query → StopTimesHelper.getTripTimesForStop()
2. Calls transitService.findPatterns(stop, true) (with realtime flag)
3. → DefaultTransitService.findPatterns() → timetableSnapshot.getPatternsForStop(stop)
4. Returns patterns from patternsForStop multimap
5. Problem: ExtraJourney patterns were never added to this index

Why the flag matters

// TimetableSnapshot.java:608-619
private void addPatternToIndex(TripPattern tripPattern) {
  if (tripPattern.isCreatedByRealtimeUpdater()) {  // ← ExtraJourneys returned FALSE
    for (var stop : tripPattern.getStops()) {
      patternsForStop.put(stop, tripPattern);  // ← Never executed for ExtraJourneys
    }
  }
}