Include auto-generated client library

Description

Following from work to create and publish a client library for typescript for the API, this should be incorporated into the frontend.

Further details

Task list

• npm add the library from source at https://gitlab.developers.cam.ac.uk/uis/devops/iam/activate-account/api/-/packages/4253
• update frontend code to use this library instead of raw axios calls/clients.

Acceptance criteria

• Frontend uses client library
• Make sure tests pass

Links/references