Issue/PR labels arc-green contrast issue introduced by #13181

[wULLSnpAXbWZGYDYyhWTKKspEQoaYxXyhoisqHf]

• Gitea version (or commit ref): Gitea version 1.14.0+dev-56-ge964c6ec1 built with GNU Make 4.3, go1.15.3 : bindata, sqlite, sqlite_unlock_notify
• Git version: git version 2.29.0.311.g38ddec7408
• Operating system: Arch Linux
• Built from source:
  • Yes
• Run with:
  • systemd
• Database:
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • No

Description

I just recently noticed there has been a change to how labels are displayed in Issue/PR feeds when using arc-green theme.
Colourful labels are gone due to an addition from #13181 , precisely - file theme-arc-green.less, line 622.
This overrides the labels original colours and everything now looks grim.
While I understand the line was added for a reason, this most certainly was not it.

Screenshots

now - grim:

before - colourful:

[6543]

ping @ivanvc

[zeripath]

And now we see why !important is a bad idea...

[ivanvc]

Darn, I had to add !important as another style was overriding the color for the labels I added. I can take this issue :D