Update action-runner.ts

needed to return promise for proper artifact chaining

app/lib/runtime/action-runner.ts

@@ -100,6 +100,7 @@ export class ActionRunner {
       .catch((error) => {
         console.error('Action failed:', error);
       });
+      return this.#currentExecutionPromise;
   }
 
   async #executeAction(actionId: string, isStreaming: boolean = false) {