Bump sass from 1.90.0 to 1.91.0

Bumps [sass](https://github.com/sass/dart-sass) from 1.90.0 to 1.91.0.
- [Release notes](https://github.com/sass/dart-sass/releases)
- [Changelog](https://github.com/sass/dart-sass/blob/main/CHANGELOG.md)
- [Commits](sass/dart-sass@1.90.0...1.91.0)

---
updated-dependencies:
- dependency-name: sass
  dependency-version: 1.91.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -66,7 +66,7 @@
     "postcss-loader": "^8.1.1",
     "prettier": "^3.6.2",
     "purgecss-webpack-plugin": "^7.0.2",
-    "sass": "^1.90.0",
+    "sass": "^1.91.0",
     "sass-loader": "^16.0.5",
     "standard": "^17.1.2",
     "stimulus": "^3.2.2",