[ATR-26264] Convenience mechanism to obtain express passed data

Additional functionality for the trig decision tool to return if a chain accepted the event into the express stream

In R3 we only allow for a secondary stream-specific prescale for the one special case of the express stream, hence the approach is targeted and not generic over prescaled streams.

The export of the required data from P1 was already covered via ATR-25956, this MR is only needed at T0 for monitoring purposes.

cc @jburr