fix: do not force-set req.destroyed = true on abort

[afharo]

The current this.req.destroyed = true hack that was added in 8b1923d actually breaks the behavior of 14.0.0.

Looking at v14.0.0's HTTP client's code, the abort method internally calls destroy.

destroy has an early termination when destroyed is already true. Setting destroyed = true before calling abort() stops Node.js from internally closing the socket, potentially leading to memory leaks.

It also breaks the behavior of abort() since Node.js deprecated it in favor of destroy() (as Node.js internally relies on destroy() logic to terminate the call.

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[titanism]

v8.1.0 released which fixes this issue, thank you

npm install superagent@8.1.0

release notes @ https://github.com/ladjs/superagent/releases/tag/v8.1.0