Create E2E tests that use real Cloudflare Workers and send the data directly to Sentry

Like we have with [react-send-to-sentry](https://github.com/getsentry/sentry-javascript/tree/63119eb1a6574f5acc3c80e8b07faf9fec357c21/dev-packages/e2e-tests/test-applications/react-send-to-sentry) we should also set up Cloudflare Workers to test things we can't locally. `wrangler` is a bit limited for some use cases and we need actual workers for that.