fix: http error caused by reusing request when refreshing token

[jbliao]

Reusing http request that contains body will cause error in #228 .
This PR recreate req.Body using req.GetBody() when retrying to fix the issue.

[Copilot]

Pull Request Overview

This PR fixes an issue where automatic token refresh fails for requests with a request body. When a 401 Unauthorized response triggers a token refresh and retry, the request body needs to be reset since it was already consumed by the first request attempt.

• Adds request body recreation logic using req.GetBody() before retry attempts
• Introduces an attempt counter to track retry attempts
• Adds a test case specifically for token refresh with POST requests that have a body
• Updates the mock HTTP client to validate request body reading

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
helix.go	Adds attempt counter and request body recreation logic before retry attempts in doRequest method
helix_test.go	Adds mock client body validation and new test case for token refresh with request bodies

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[Copilot]

The code relies on req.GetBody being set, but newJSONRequest doesn't explicitly set this field. While http.NewRequestWithContext may automatically set GetBody for *bytes.Buffer, this is not guaranteed for all cases and could lead to silent failures where retry attempts fail without proper error handling. Consider explicitly setting req.GetBody in newJSONRequest after creating the request, like: req.GetBody = func() (io.ReadCloser, error) { return io.NopCloser(bytes.NewBuffer(b)), nil }