* feat(alerting): add support for including endpoint errors in custom alerts
- Updated `buildHTTPRequest` method in `AlertProvider` to accept a `result` parameter.
- Added support for including `[ENDPOINT_ERRORS]` in both the request body and URL, which will be replaced by the errors from `Result.Errors[]`.
- Adjusted `CreateExternalEndpointResult` to capture and store errors from query parameters.
- This allows custom alerts to include detailed error information, enhancing the flexibility of alert notifications.
* feat: add ENDPOINT_ERRORS example
* feat: add tests
* Refactor: code review feedback
* delete unsed errors
* Update README.md
* Apply suggestions from code review
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Co-authored-by: raojinlin <raojinlin302@gmail.com>
Co-authored-by: TwiN <twin@linux.com>