Use hide-when-empty as a class, so CSS will work correctly

[sippsolutions]

horizon/assets/base.css:488 lists

.hide-when-empty:empty {
  /* stylelint-disable-next-line declaration-no-important */
  display: none !important;
}

which will not work for the <span> which uses hide-when-empty as an attribute instead of a class.

[brandtam]

This works and fixes a bug