allow "latest" to be used in release vTag when downloading file (#26748)

allow "latest" to be used in release vTag when downloading file (#26748)

Hello,

In the discord I saw
[someone](https://discord.com/channels/322538954119184384/1069795723178160168/1145061200644800514)
complaining that you can't use the "latest" keyword as release tag to
download a specific file:
In his example:

https://www.uberwald.me/gitea/public/fvtt-ecryme/releases/latest/system.json

However the latest keyword works for the release page, so I think it's a
good thing to implement this on the release attachment download url too.

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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>