Adds a new permission "Assign this type to host entity registration fields" per registration type. This allows site builders to vary the allowed registration type values for registration fields by user role. Most sites can leave this option disabled. See <a href="https://www.drupal.org/project/registration/issues/1683116" target="_blank">this issue on Drupal.org</a> for more information. Note that site builders can already restrict the allowed values per host entity bundle using the "Allowed types" registration field setting, however that restriction is global and affects all users equally.