(feat): Global user mobile e2e

In order for #907 (closed) & #903 (closed) to work correctly, they will need to share a common user, as messenger will need a fresh user so that the onboarding messenger password step is not skipped.

This user will have to be created by manually calling the create user endpoint, and then the users details can be assigned to global vars to be used in any needed tests. Doing this means that the login action can then be adapted to skip any onboarding steps that are present, and as a result we could run the tests asynchronously.