1. Is this a client library issue or a product issue?
   Product

2. Did someone already solve this?
   Not that I know of.

3. Do you have a support contract?
   No

Environment details

• OS: Ubuntu, Windows, Mac
• Node.js version: 20.10.0
• npm version: 10.2.5
• @google-cloud/pubsub version: 4.3.0

Steps to reproduce

After upgrading to 4.3.0, there's an error without proper stacktrace due to asynchronous usage that seems to be coming out of the createSubscription method invocation:

TypeError: this.auth.getUniverseDomain is not a function
    at GrpcClient.createStub (/usr/engineering/backend/node_modules/google-gax/src/grpc.ts:418:48)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)

Everything works when reverting to 4.2.0.