Bump govuk_ab_testing from 2.4.2 to 2.4.3

Bumps [govuk_ab_testing](https://github.com/alphagov/govuk_ab_testing) from 2.4.2 to 2.4.3.
- [Release notes](https://github.com/alphagov/govuk_ab_testing/releases)
- [Changelog](https://github.com/alphagov/govuk_ab_testing/blob/main/CHANGELOG.md)
- [Commits](alphagov/govuk_ab_testing@v2.4.2...v2.4.3)

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

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

Gemfile.lock

@@ -123,7 +123,7 @@ GEM
       rest-client (~> 2.0)
     globalid (1.1.0)
       activesupport (>= 5.0)
-    govuk_ab_testing (2.4.2)
+    govuk_ab_testing (2.4.3)
     govuk_app_config (5.1.0)
       logstasher (~> 2.1)
       plek (>= 4, < 6)