[Flaky CI]: correctly applies isolation scope even without tracing

### Flakiness Type

Assertion failure - probably race condition

### Name of Job

Node (18) Integration Tests

### Name of Test

suites/express/without-tracing/test.ts

### Link to Test Run

https://github.com/getsentry/sentry-javascript/actions/runs/10214714110/job/28263007785?pr=13174#step:6:429

### Details

_No response_