Bump govuk_app_config from 9.3.0 to 9.4.0

Bumps [govuk_app_config](https://github.com/alphagov/govuk_app_config) from 9.3.0 to 9.4.0.
- [Changelog](https://github.com/alphagov/govuk_app_config/blob/main/CHANGELOG.md)
- [Commits](alphagov/govuk_app_config@v9.3.0...v9.4.0)

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

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

Gemfile.lock

@@ -146,7 +146,7 @@ GEM
     google-protobuf (3.24.4-x86_64-linux)
     googleapis-common-protos-types (1.9.0)
       google-protobuf (~> 3.18)
-    govuk_app_config (9.3.0)
+    govuk_app_config (9.4.0)
       logstasher (~> 2.1)
       opentelemetry-exporter-otlp (>= 0.25, < 0.27)
       opentelemetry-instrumentation-all (>= 0.39.1, < 0.51.0)