Enable chunked transfer encoding for Git LFS uploads by adding
Transfer-Encoding: chunked header to upload action responses. This
prevents large file uploads (100+ MB) from being blocked by reverse
proxies like Cloudflare that buffer non-chunked requests.
Fix https://github.com/go-gitea/gitea/issues/22233
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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>