fix wrong AbortSignal ctor

Author: geropl

components/server/src/messaging/redis-subscriber.ts

@@ -58,7 +58,7 @@ export class RedisSubscriber {
 
         this.redis.on("message", async (channel: string, message: string) => {
             const ctx = {
-                signal: new AbortSignal(),
+                signal: new AbortController().signal,
                 requestKind: "redis-subscriber",
                 requestMethod: channel,
                 subjectId: SubjectId.fromUserId(SYSTEM_USER),