Bump govuk_design_system_formbuilder from 5.1.0 to 5.4.0

Bumps [govuk_design_system_formbuilder](https://github.com/x-govuk/govuk-form-builder) from 5.1.0 to 5.4.0.
- [Release notes](https://github.com/x-govuk/govuk-form-builder/releases)
- [Commits](x-govuk/govuk-form-builder@v5.1.0...v5.4.0)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -151,7 +151,7 @@ GEM
       dotenv (= 3.1.2)
       railties (>= 6.1)
     drb (2.2.1)
-    erubi (1.12.0)
+    erubi (1.13.0)
     execjs (2.9.1)
     factory_bot (6.2.1)
       activesupport (>= 5.0.0)
@@ -165,7 +165,7 @@ GEM
       html-attributes-utils (~> 1.0.0, >= 1.0.0)
       pagy (~> 6.0)
       view_component (>= 3.9, < 3.11)
-    govuk_design_system_formbuilder (5.1.0)
+    govuk_design_system_formbuilder (5.4.0)
       actionview (>= 6.1)
       activemodel (>= 6.1)
       activesupport (>= 6.1)
@@ -234,7 +234,7 @@ GEM
     net-smtp (0.5.0)
       net-protocol
     nio4r (2.7.1)
-    nokogiri (1.16.5)
+    nokogiri (1.16.6)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     pagy (6.5.0)