A few other things were also removed as they were no longer being used:

- The `create_merge_request_button.vue` component, since the SAST
  Configuration UI would always now be available instead
- The `SastConfigurationController#create` action, since only the above
  button used that endpoint. (The `configureSast` GraphQL mutation is
  used instead of this endpoint elsewhere.)

Addresses https://gitlab.com/gitlab-org/gitlab/-/issues/235135.