`terraform-apply-development` from a feature branch via the gitlab UI

As a developer,
I want to preview and `terraform-apply-development` changes from a feature branch via the gitlab UI prior to merge,
So that I can ensure changes to the GCP development environment are consistent with the changes on the feature branch and not ad-hoc changes from a local developer machine.

For example, pipeline https://gitlab.developers.cam.ac.uk/uis/devops/hr/tes/tes-infrastructure/-/pipelines/623890/ would have the same terraform-apply-development button that appears in pipeline https://gitlab.developers.cam.ac.uk/uis/devops/hr/tes/tes-infrastructure/-/pipelines/623067