Make `@sentry/aws-serverless` and `@sentry/google-cloud-serverless` ESM compat

[AbhiPrasad]

The serverless SDKs use require to monkeypatch GCP and AWS related libraries. This does not work with ESM (and it gets even more complicated with bundling).

For now we made those SDKs CJS only, but we should investigate a long term solution to make these packages work with ESM.

### Tasks
- [ ] https://github.com/getsentry/sentry-javascript/pull/11548
- [ ] https://github.com/getsentry/sentry-javascript/issues/11776