foxy-customer-portal: Show prompt to update password if authenticating with temporary password

[adamjudd]

If you log in to the customer portal using a temporary password, we should prompt the user to update their password straight away. The temporary passwords are designed for single-use access, so once they use it to log in, their next step should be to set a new password.

This may also necessitate an update to the API to identify in the login response for whether a password reset prompt should be required. The foxy-sign-in-form is built to handle a forced new password if a login response of { "code": "new_password_required" } is returned.