Metricbeat: `metricbeat/mb/testing/data TestAll` fails on macOS 14/15

## Flaky Test

* **Test Name:** metricbeat/mb/testing/data TestAll.
* **Link:** https://github.com/elastic/beats/blob/8920a05987a2ea5703d50f92d8d0bebfe9e65e32/metricbeat/mb/testing/data/data_test.go#L35-L55
* **Branch:** main.
* **Artifact Link:** https://github.com/elastic/beats/actions/runs/14169372171/job/39689574970?pr=43520#step:3:950
* **Notes:** Additional details about the test. e.g. theory as to failure cause

### Stack Trace

```
testdata.go:340: Event was not expected: {"event":{"dataset":"kubernetes.apiserver","duration":115000,"module":"kubernetes"},"kubernetes":{"apiserver":{"major":{"version":"1"},"minor":{"version":"21"},"request":{"component":"apiserver","duration":{"us":{"bucket":{"+Inf":3},"count":3,"sum":1413001212.8630002}},"group":"discovery.k8s.io","longrunning":{"count":1},"resource":"endpointslices","scope":"cluster","verb":"WATCH","version":"v1"},"response":{"size":{"bytes":{"bucket":{"+Inf":3,"1000":3,"10000":3,"100000":3,"1000000":3,"10000000":3,"100000000":3,"1000000000":3},"count":3,"sum":0}}}}},"metricset":{"name":"apiserver","period":10000},"service":{"address":"127.0.0.1:55555","type":"kubernetes"}}
```

Start with metricbeat/mb/testing/data/data_test.go#L35-L55 and run TestAll on macOS 14 or 15, using the linked GitHub Actions artifact and stack trace as failure references. Investigate the unexpected Kubernetes apiserver event and determine what makes the test fail on those macOS versions; done means TestAll passes reliably there.

Written by the indexing model from the issue text.