test(node): Unflake captureMessage with_level test (#25358)

The `with_level` scenario sends six `captureMessage` calls back to back,
and the test expected their events to arrive in call order. Events are
prepared asynchronously before being sent, so the SDK doesn't guarantee
that order, and the test occasionally failed with `info_message`
arriving before `debug_message`. The test now uses `.unordered()`, so it
still asserts all six messages with their levels but no longer depends
on arrival order.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: mydea

dev-packages/node-integration-tests/suites/public-api/captureMessage/with_level/test.ts

@@ -13,6 +13,7 @@ test('should capture with different severity levels', async () => {
     .expect({ event: { message: 'error_message', level: 'error' } })
     .expect({ event: { message: 'fatal_message', level: 'fatal' } })
     .expect({ event: { message: 'log_message', level: 'log' } })
+    .unordered()
     .start()
     .completed();
 });