When creating attachments (issue, release, repo) the file size (being
part of the multipart file header) is passed through the chain of
creating an attachment to ensure the MinIO client can stream the file
directly instead of having to read it to memory completely at first.
Fixes#23393
Co-authored-by: KN4CK3R <admin@oldschoolhack.me>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>