fix: let the CVE timeline rules pass stylelint so PR CI runs green again

[silentoplayz]

Summary

Every pull request against this repository has failed the CI workflow since the CVE timeline styles landed in src/css/custom.css. The Run stylelint step reports three no-descending-specificity errors on main itself (the table tr:has(.cve-rejected) pair and .cve-resolved .theme-admonition), and nothing on main runs stylelint because the workflow is triggered by pull_request only, so the failure shows up on other people's PRs and never on the commit that caused it.

This adds a stylelint-disable-next-line no-descending-specificity comment above each of the three rules, which is how the rest of the file already handles the same rule for the table styles. No selector or declaration changes, so the rendered site is unchanged. npm run stylelint passes with this commit.

Related issue or discussion

None. The failing runs are visible on #1387, #1388, #1390, #1395 and #1396.

Checklist

• I have reviewed the relevant documentation and matched the existing style.
• This PR meets Open WebUI's contribution standards: it is accurate, relevant to users, narrowly scoped, maintainable, and not promotional content, advertising, lead generation, SEO placement, or a request to list a product, service, provider, integration, gateway, tool, or company primarily for visibility.
• I understand that PRs that do not meet these standards may be closed without review and will not be merged. Repeated, low-quality, off-topic, promotional, or intentionally misleading submissions may result in the contributor being blocked from future participation in Open WebUI repositories.

Notes for reviewers

Reproduced locally with the repository's own stylelint on main's custom.css: three errors before, none after. Once this merges, the open PRs go green on their next run without changes of their own.