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/Spells/Eighth/SummonDaemon.cs

@@ -43,7 +43,12 @@ namespace Server.Spells.Eighth
         {
             if (CheckSequence())
             {
-                var duration = TimeSpan.FromSeconds(2 * Caster.Skills.Magery.Fixed / 5);
+                var duration = Core.Expansion switch
+                {
+                    Expansion.None => TimeSpan.FromSeconds(Caster.Skills.Magery.Value),
+                    // T2A -> Current
+                    _ => TimeSpan.FromSeconds(4 * Math.Min(5, Caster.Skills.Magery.Value)),
+                };
 
                 if (Core.AOS) /* Why two diff daemons? TODO: solve this */
                 {