Performance Regression or Improvement: gbk_python_batch_load_test_fanout_4_times_with_2GB_10byte_records_total:runtime

Performance change found in the
test: `gbk_python_batch_load_test_fanout_4_times_with_2GB_10byte_records_total` for the metric: `runtime`.

For more information on how to triage the alerts, please look at
`Triage performance alert issues` section of the [README](https://github.com/apache/beam/tree/master/sdks/python/apache_beam/testing/analyzers/README.md#triage-performance-alert-issues).

`Test description:` GroupByKey Python Load test - fanout 4 times with 2GB 10-byte records total
python | GBK | Fanout 4
Test Dashboard - http://metrics.beam.apache.org/d/UYZ-oJ3Zk/gbk-load-tests?orgId=1&var-processingType=batch&var-sdk=python&from=now-90d&to=now&viewPanel=5
Test link - https://github.com/apache/beam/blob/5e38decf9e723a385057131b01bbd33d8c60bda3/.test-infra/jenkins/job_LoadTests_GBK_Python.groovy#L106

```

timestamp: Sat May 23 17:28:35 2026, metric_value: 96.00
timestamp: Fri May 22 17:52:57 2026, metric_value: 116.00
timestamp: Thu May 21 18:24:06 2026, metric_value: 108.00 <---- Anomaly
timestamp: Wed May 20 18:06:39 2026, metric_value: 59.00
timestamp: Tue May 19 18:08:34 2026, metric_value: 52.00
timestamp: Mon May 18 18:03:17 2026, metric_value: 89.00
timestamp: Sun May 17 17:30:46 2026, metric_value: 71.00
timestamp: Sat May 16 17:23:24 2026, metric_value: 72.00
timestamp: Fri May 15 17:48:57 2026, metric_value: 95.00
timestamp: Thu May 14 17:40:23 2026, metric_value: 70.00
timestamp: Wed May 13 17:57:04 2026, metric_value: 68.00
timestamp: Tue May 12 17:46:34 2026, metric_value: 85.00
timestamp: Mon May 11 18:04:01 2026, metric_value: 75.00

```