Drupal8: Buggy behavior if user account is created without email address

In Drupal 8, the email address isn't a required field. However, if an email address isn't specified, then the civicrm_uf_match record isn't created, the corresponding CiviCRM contact isn't created, and this leads to some very buggy behavior, such as the dashboard showing multiple dashboards (see #54 (comment 23706)), which I imagine is because civicrm_dashboard_contact is being queried by contact ID, and finding none, simply loads all dashlets for all users.

I think the correct way to handle this is to use a Drupal hook to make the email address required.