language: Fix no diagnostics are shown for CSS (#35663)
Closes #30499
`vscode-css-language-server` throws a null reference error if no
workspace configuration is provided from the client.
Release Notes:
- Fixed issue where no diagnostics were shown for CSS, LESS, and SCSS.
cf23f93917Smit Barmase committed on 8/5/2025, 8:28:23 PM· committed by GitHubparent6b77654