build: bump govuk_frontend_toolkit from 7.4.1 to 7.4.2
build: bump govuk_frontend_toolkit from 7.4.1 to 7.4.2

Bumps [govuk_frontend_toolkit](https://github.com/alphagov/govuk_frontend_toolkit) from 7.4.1 to 7.4.2.
- [Changelog](https://github.com/alphagov/govuk_frontend_toolkit/blob/master/CHANGELOG.md)
- [Commits](https://github.com/alphagov/govuk_frontend_toolkit/compare/v7.4.1...v7.4.2)
ministryofjustice/prison-visits-public,ministryofjustice/prison-visits-public,ministryofjustice/prison-visits-public,ministryofjustice/prison-visits-public