fix: Fixes spell mechanics and misc bugs (#1118)

- [X] Fixes NPE from account tags.
- [X] Fixes bad skill check due to missing cast to double.
- [X] Fixes water elemental duration.
- [X] Standardizes spell summon duration by expansion.

Projects/UOContent/Engines/Craft/Core/CraftSystem.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using Server.Items;
 
 namespace Server.Engines.Craft