fix: added mythos fragment to event sack (#2189)

Author: Trendt

constants/sacks.json

@@ -687,7 +687,8 @@
         "FISHY_TREAT",
         "JACOBS_TICKET",
         "AGATHA_COUPON",
-        "ENCHANTED_ANCIENT_CLAW"
+        "ENCHANTED_ANCIENT_CLAW",
+        "MYTHOS_FRAGMENT"
       ]
     }
   }