Bump govuk_ab_testing from 2.4.3 to 3.0.0

Bumps [govuk_ab_testing](https://github.com/alphagov/govuk_ab_testing) from 2.4.3 to 3.0.0.
- [Changelog](https://github.com/alphagov/govuk_ab_testing/blob/main/CHANGELOG.md)
- [Commits](alphagov/govuk_ab_testing@v2.4.3...v3.0.0)

---
updated-dependencies:
- dependency-name: govuk_ab_testing
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Gemfile.lock

@@ -201,7 +201,7 @@ GEM
       nokogiri (~> 1.12)
       rinku (~> 2.0)
       sanitize (~> 6)
-    govuk_ab_testing (2.4.3)
+    govuk_ab_testing (3.0.0)
     govuk_app_config (9.14.0)
       logstasher (~> 2.1)
       opentelemetry-exporter-otlp (>= 0.25, < 0.29)