Bump @navikt/ds-css from 5.11.4 to 5.12.1 in /app

Bumps [@navikt/ds-css](https://github.com/navikt/aksel) from 5.11.4 to 5.12.1.
- [Release notes](https://github.com/navikt/aksel/releases)
- [Changelog](https://github.com/navikt/aksel/blob/main/CHANGELOG.md)
- [Commits](https://github.com/navikt/aksel/compare/@navikt/ds-css@5.11.4...@navikt/ds-css@5.12.1)

---
updated-dependencies:
- dependency-name: "@navikt/ds-css"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

app/package.json

@@ -4,7 +4,7 @@
   "private": true,
   "homepage": ".",
   "dependencies": {
-    "@navikt/ds-css": "^5.11.4",
+    "@navikt/ds-css": "^5.12.1",
     "@navikt/ds-css-internal": "^3.4.3",
     "@navikt/ds-react": "^5.12.1",
     "@navikt/ds-react-internal": "^3.4.3",