Hasura CLI v1.2.0-beta.4 keeps on showing spinner

Hi!

I noticed that when running `hasura console` in v1.2.0-beta.4, the CLI leaves the "Opening console using default browser...◑" spinner running until you stop the process.

```
env-cmd -f .env hasura console
INFO hasura cli is up to date version=1.2.0-beta.4
INFO console running at: http://localhost:9695/
Opening console using default browser...◑
```

It was working alright in beta.3. This isn't a big deal but it's somewhat annoying because it puts a spinner on the terminal tab too and it draws the attention towards it. For now I'm starting it with `--no-browser`.

I looked into the code but don't know what might be off with it since I'm not familiar with Go and its flow seems alright at first sight.

Thanks!