Bump govuk-frontend from 5.6.0 to 5.7.1

Bumps [govuk-frontend](https://github.com/alphagov/govuk-frontend) from 5.6.0 to 5.7.1.
- [Release notes](https://github.com/alphagov/govuk-frontend/releases)
- [Changelog](https://github.com/alphagov/govuk-frontend/blob/main/CHANGELOG.md)
- [Commits](alphagov/govuk-frontend@v5.6.0...v5.7.1)

---
updated-dependencies:
- dependency-name: govuk-frontend
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -11,7 +11,7 @@
     "@x-govuk/govuk-prototype-components": "^3.0.9",
     "dotenv": "^16.4.5",
     "express": "~4.21.1",
-    "govuk-frontend": "^5.5.0",
+    "govuk-frontend": "^5.7.1",
     "nunjucks": "^3.2.4",
     "sass": "^1.80.3"
   },