Spell list ability modifier can take non-abilities

defaults to .value if .modifier is undefined
is now undefined for no .modifier or .value

app/imports/api/engine/computation/computeComputation/computeByType/computeSpellList.js

@@ -2,5 +2,9 @@ export default function computeSpelllist(computation, node) {
   const prop = node.data;
 
   const ability = computation.scope[prop.ability];
-  prop.abilityMod = ability?.modifier || 0;
-}
+  if (Number.isFinite(ability?.modifier)) {
+    prop.abilityMod = ability.modifier;
+  } else if (Number.isFinite(ability?.value)) {
+    prop.abilityMod = ability.value;
+  }
+}