Adjusts Extended Ammunition default sell prices (#7125)

* Fixes #7098.
* Adjusts the Extended Ammunition NPCs to use the default prices set via the item database.
Thanks to @Badarosk0!

npc/re/merchants/Extended_Ammunition.txt

@@ -191,7 +191,7 @@ OnInit:
 //============================================================
 
 //= Archer
--	marketshop	Arrow_Archer	HIDDEN_NPC,1750:-1:-1,1770:3:-1,1751:5:-1,1752:5:-1,1754:5:-1,1755:5:-1,1756:5:-1,1757:5:-1,1767:5:-1,1762:5:-1,1065:50:-1,7940:100:-1
+-	marketshop	Arrow_Archer	HIDDEN_NPC,1750:-1:-1,1770:-1:-1,1751:-1:-1,1752:-1:-1,1754:-1:-1,1755:-1:-1,1756:-1:-1,1757:-1:-1,1767:-1:-1,1762:-1:-1,1065:-1:-1,7940:-1:-1
 
 //= Gunslinger
 -	shop	Weapons_Gunslinger	-1,13120:-1,13122:-1,13189:-1,13195:-1,13192:-1,13193:-1,13194:-1,13197:-1,13198:-1,28200:-1,28201:-1