C# 9 Cleanup (#325)

- [X] Removes EventArgs - not needed
- [X] Merges sequential checks
- [X] Removes redundant type declarations

Projects/UOContent/Items/Containers/TreasureMapChest.cs

@@ -10,7 +10,7 @@ namespace Server.Items
 {
     public class TreasureMapChest : LockableContainer
     {
-        private List<Item> m_Lifted = new List<Item>();
+        private List<Item> m_Lifted = new();
 
         private Timer m_Timer;