Backport #30215 by @silverwind
On the labels list, This `left` class caused the dropdown content to
flash on page load until JS had hidden it. Remove it as I see no purpose
to it.
<img width="215" alt="image"
src="https://github.com/go-gitea/gitea/assets/115237/9e1de97f-dd89-41e0-9229-5c4a786ba762">
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
(cherry picked from commit 3ff4a6936b5ee05b3df945c466285de47ea87ef2)
Likely still a few useless classes left, but I think I at least don't
have missed any.
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: Giteabot <teabot@gitea.io>
---
Conflict resolution: Trivial
Ref: https://codeberg.org/forgejo/forgejo/issues/2776
(cherry picked from commit f22fe4e1944d8084dec7c04f064a8e782fca94d4)