fix(res.send): add Content-Length header only if Transfer-Encoding is not present (#4893)

* fix(respond): add Content-Length header only if Transfer-Encoding is not present

* fix(response): used get('Transfer-Encoding')

* test(res.send): covered Transfer-Encoding and Content-Length headers logic

* chore(response): removed comment

* chore(res.redirect): revert changes to focus on res.send

* test(res.send): added tests for all transfer encodings

* docs: update History.md to include bug fix for HTTP header conflict in res.send()

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Co-authored-by: Sebastian Beltran <bjohansebas@gmail.com>