HFP-3989 Fix programmatically removing a list item

[otacke]

When merged in, will remove the list editor's item element ($item) not only when removing the item via the GUI, but when programmatically removing the underlying list item.

Currently, the list editor item gets removed properly when using the GUI and when clicking on the remove button. If one calls removeItem on the underlying list instance, however, the list editor's item element ($item) is not removed.