Fix and clean up `ConfirmModal` (#31283) (#31291)
Backport #31283 by @silverwind
Bug: orange button color was removed in
https://github.com/go-gitea/gitea/pull/30475, replaced with red
Bug: translation text was not html-escaped
Refactor: Replaced as much jQuery as possible, added useful
`createElementFromHTML`
Refactor: Remove colors checks that don't exist on `.link-action`
<img width="381" alt="image"
src="https://github.com/go-gitea/gitea/assets/115237/
5900bf6a-8a86-4a86-b368-
0559cbfea66e">
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>