**Related issue:** Resolves#44428
Unreleased bug from #48452 caught during testing
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## Summary by CodeRabbit
* **Bug Fixes**
* Improved handling of resource-conflict responses when wording varies,
including singular and plural message formats.
* Prevented authentication failures and unrelated bad requests from
being incorrectly classified as conflicts.
* **Tests**
* Added coverage for HTTP conflict responses, recognized conflict types,
message variations, and non-conflict errors.
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