Show confidential button in work item action menu when parent is confidential

Problem

Currently in a work item, if this item and its parent are confidential, the confidential action is not shown in the menu. While users are unable to change confidentiality in this scenario — due to rules requiring parent/child both being confidential — it's impossible for a user to tell this is the case. The action is simply missing, with no context why.

Solution

• Any time a user has permission to change confidentiality, show the confidential action in the menu

• If the parent is confidential, disable the "Turn off confidentiality" action button and show a tooltip on hover:

  Child items of a confidential parent must be confidential. Turn off confidentiality on the parent item first.

Alternately, if #368318 (closed) is completed this is no longer relevant.