Cryomancer
Arcane
The skeleton summon indeed passes through the trap without harm. But then the party has to pass through, and the trap is still there. And why do you assume this is a lich trap and the party has death wards for everyone? It could easily be part of, say, a lord's treasury defences.
Nigga, no one says it will kill your skellington. I'm saying exactly opposite - you wouldn't know if there are death or mindfuck traps in corridor he "disarmed" exactly because he would be unaffected.
Is the trap loud? wail has a verbal component. Unless this tier 9 spell is somehow "silent spell", the party would hear the trap triggering. And as I've said, any party should have deathward in that situation. And I assume that death ward is available to everyone since it is a 4th level spell available in many wands and we are talking about a high level dungeon which tier 9 spells on traps.
Vordakai's Tomb on Kingmaker has only tier 5/6/7 magic on their traps and is a pretty nasty dungeon in therms of traps.