Blackrock - Add Challenge NPC to Twink Island

Hey,

My suggestion is to add a Challenge NPC to the Twink Island on Blackrock.
The arena NPCs are already added to the island, so there is precedent of such a change.
This would just be a quality of life improvement, as dueling is a large part of 19s twinking, but many people do not even know that the Challenge NPC exists in Dalaran.

Thanks