fix dispatcher active

src/workflow-dispatcher.ts

@@ -443,7 +443,7 @@ export class WorkflowDispatcher<F extends (...args: any[]) => Promise<any>> {
   private isEligibleActive(i: number, now: number) {
     const slot = this.slots[i] as ActiveSlot<F>;
     const slotGood = (s: ActiveSlot<F>) =>
-      s.kind === 'active' && !s.state.running;
+      s.kind === 'active' && !s.state?.running;
     if (!slotGood(slot)) return false;
     if (now >= slot.state.nextAvailableAt) return true;
     return !this.slots.some((other: ActiveSlot<F>, j) => {