3542: Need to disable CSRF for compatibility with old frontend
3542: Need to disable CSRF for compatibility with old frontend

We can't have CSRF enabled for the SignInController's select_idp
endpoint in the interests of ZDD.

Authors: 93052164ceb48fea775e92bd978ff1509c76163d@vixus0

alphagov/verify-frontend,alphagov/verify-frontend,alphagov/verify-frontend,alphagov/verify-frontend