EditableList's "delete" action-suppression condition is flipped

Description

EditableList's "delete" condition in the action-suppression handler is inverted.

Expected behavior

The "delete" button is displayed IFF the suppression-function returns "false" for a given item; i.e. if the delete is NOT being suppressed.

Actual behavior

The delete button is displayed when the suppression-function returns "true" for a given item.