NPM: Bump sass from 1.79.4 to 1.81.0 in /frontend

Bumps [sass](https://github.com/sass/dart-sass) from 1.79.4 to 1.81.0.
- [Release notes](https://github.com/sass/dart-sass/releases)
- [Changelog](https://github.com/sass/dart-sass/blob/main/CHANGELOG.md)
- [Commits](sass/dart-sass@1.79.4...1.81.0)

---
updated-dependencies:
- dependency-name: sass
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

frontend/package-lock.json

@@ -20,7 +20,7 @@
         "eslint-plugin-svelte": "^2.46.0",
         "prettier": "^3.3.3",
         "prettier-plugin-svelte": "^3.2.7",
-        "sass": "^1.79.4",
+        "sass": "^1.81.0",
         "svelte": "^4.2.19",
         "svelte-check": "^4.0.8",
         "tslib": "^2.7.0",