More abilities, refactor custom triggers to be typed.

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/IceBody.cs

@@ -41,11 +41,10 @@ public class IceBody : Script
     }
 
     /// <inheritdoc />
-    public override void CustomTrigger(StringKey eventName, IDictionary<StringKey, object?>? parameters)
+    public override void CustomTrigger(StringKey eventName, ICustomTriggerArgs args)
     {
-        if (eventName != CustomTriggers.IgnoreHail || parameters is null)
+        if (eventName != CustomTriggers.IgnoreHail || args is not CustomTriggers.IgnoreHailArgs ignoreHailArgs)
             return;
-
-        parameters["ignoresHail"] = true;
+        ignoreHailArgs.Ignore = true;
     }
 }