[Flaky Test] github.com/elastic/beats/v7/filebeat/input/filestream TestFilestreamDeleteFileRemoveRetries

## Flaky Test

* **Test Name:** TestFilestreamDeleteFileRemoveRetries
* **Scope:** github.com/elastic/beats/v7/filebeat/input/filestream
* **File:** N/A
* **Location:** N/A
* **Buildkite Link:** https://buildkite.com/organizations/elastic/analytics/suites/beats/tests/6d825a36-1738-88f5-80e0-8b89a118d53e
* **Flaky Instances:** 1
* **Latest Occurrence:** 2026-04-08T08:07:25.717Z

### Details

```json
{
"id": "6d825a36-1738-88f5-80e0-8b89a118d53e",
"web_url": "https://buildkite.com/organizations/elastic/analytics/suites/beats/tests/6d825a36-1738-88f5-80e0-8b89a118d53e",
"scope": "github.com/elastic/beats/v7/filebeat/input/filestream",
"name": "TestFilestreamDeleteFileRemoveRetries",
"location": null,
"file_name": null,
"instances": 1,
"latest_occurrence_at": "2026-04-08T08:07:25.717Z",
"most_recent_instance_at": "2026-04-08T08:07:25.717Z",
"last_resolved_at": null,
"ownership_team_ids": [],
"failure_examples_count": 1
}
```

### Failure Examples

**Example 1:**
**Run:** https://api.buildkite.com/v2/analytics/organizations/elastic/suites/beats/runs/c4494b13-5e51-8634-b96e-9e34cbcb414c
**Time:** 2026-04-08T06:49:30.761Z
**Stacktrace:**

```
=== RUN TestFilestreamDeleteFileRemoveRetries
logger.go:108: Full logs written to ../../build/integration-tests/testing-logger-3982783572.log
--- FAIL: TestFilestreamDeleteFileRemoveRetries (1.01s)

```

Start with TestFilestreamDeleteFileRemoveRetries in github.com/elastic/beats/v7/filebeat/input/filestream and reproduce it using the linked Buildkite run and failure logs. Trace the test and the file-removal retry behavior to identify the intermittent failure; done means the test reliably passes without masking a real failure.

Written by the indexing model from the issue text.