Local Variables not being reported when hosting on Vercel

### Is there an existing issue for this?

- [x] I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
- [x] I have reviewed the documentation https://docs.sentry.io/
- [x] I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

### How do you use Sentry?

Sentry Saas (sentry.io)

### Which SDK are you using?

@sentry/nextjs

### SDK Version

9.2.0

### Framework Version

Next 15.2.0

### Link to Sentry event

https://aerial-ops.sentry.io/issues/6340230618/events/4b04a367762c4da59f3ffc5d112adccb/?project=6255059

### Reproduction Example/SDK Setup

GitHub repo: https://github.com/cau777/temp-sentry-nextjs-localvars

### Steps to Reproduce

1. Create a NextJS project using [create-next-app](https://nextjs.org/docs/app/api-reference/cli/create-next-app): `npx create-next-app@latest temp-sentry-nextjs-localvars`
2. Install Sentry with the wizard: `npx @sentry/wizard@latest -i nextjs`
3. Add `includeLocalVariables: true` to `sentry.server.config.ts`
4. Implement a test function under `pages/api`, for example:
```js
const willThrow = () => {
const hey = 12
const value = 1
const str = "some string"
console.log(hey, value, str)
throw new Error("Intentional error on Sentry reproduction 3")
}

export default function handler(_req, res) {
try {
willThrow()
} catch (e) {
captureException(e)
}

res.status(200).json({ name: "John Doe" });
}
```
5. Upload the project to a git repo and deploy to [Vercel](https://vercel.com/)
6. Add `SENTRY_AUTH_TOKEN` to the env variables in Vercel

### Expected Result

When navigating to the test API route on the deployed app, an error should be reported to Sentry, containing all 3 local variables from the `willThrow` function.

### Actual Result

No local variables appear in the Sentry issue when the app is deployed on Vercel.


However, running the same code locally `npm run dev` reports local variables to Sentry as expected.

https://aerial-ops.sentry.io/issues/6340144143/events/d4f46bc86efa400db9fac4c8c8f5e8c1/?project=6255059


Vercel apps are deployed on AWS Lambda, maybe the debugger used by Sentry to extract local variables doesn't work in that environment?