`JobsClient.checkRunJobProgress` not implemented, or supported, or enabled.

> I am not sure whether this issue belongs to the `google-gax` library (this repo) or to the [`@google-cloud/run` library](https://github.com/googleapis/google-cloud-node/). However, creating an issue in the latter is pretty intimidating because of the many things they request (e.g. a link to a public Github Repository or gist with a minimal reproduction).

Calling `JobsClient.checkRunJobProgress` returns the following error:

```
12 UNIMPLEMENTED: Operation is not implemented, or supported, or enabled.
```

According to [this troubleshooting guide](https://cloud.google.com/run/docs/troubleshooting#operation-not-supported), this happens when an incorrect region is provided. I am certain this is not the case. Moreover, performing the underlying (get operation) request via cURL works just fine:

```bash
curl -X GET \
-H "Authorization: Bearer $(gcloud auth print-access-token)" \
"https://run.googleapis.com/v2/projects/${PROJECT}/locations/${LOCATION}/operations/${OPERATION_ID}"
```

#### Environment details

- OS: macOS Sonoma 14.4.1
- Node.js version: v18.20.0
- npm version: 10.5.0
- `gax-nodejs` version: 4.3.2

#### Steps to reproduce

1. Instantiate the `JobsClient`
2. Run a job
3. Check the progress for the operation returned by the run job method

```tsx
import { JobsClient } from '@google-cloud/run'

const client = new JobsClient()

const [operation] = await client.runJob({ name: `projects/${PROJECT}/locations/${JOB_LOCATION}/jobs/${JOB}` })

await client.checkRunJobProgress(operation.name) // this will throw 💥
```