Fix unreleased bug #30693.
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## Summary by CodeRabbit
* **Documentation**
* Updated testing documentation to include a missing command for
creating the Firehose delivery stream for "status" logs.
* **Refactor**
* Centralized AWS STS Assume Role credential configuration across
multiple AWS integrations (S3, Firehose, Kinesis, Lambda, SES) to use a
shared helper, improving maintainability and consistency.
* Removed deprecated inline credential configuration logic in favor of
the new centralized approach.
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