fix: handle undefined values when giving damage

There is an issue with unlinked tokens that sometimes the code is trying
to access data  which does not exist. This fix makes prevents this from
happening

src/module/hooks/updateHits.ts

@@ -26,7 +26,7 @@ Hooks.on('preUpdateToken', async (scene, token:Record<string, any>, update:Recor
     const actor = TwodsixActor.collection.get(token.actorId);
     update.actorData.data.hits = getCurrentHits(
       actor.data.data.characteristics,
-      token.actorData.data.characteristics,
+      token.actorData?.data?.characteristics ?? {},
       update.actorData.data.characteristics
     );
   }