No event for checkbox de-selection

[ThomasThelen]

Given a node tree with checkboxes, developers can tell when someone selects the checkbox by listening for the focus event. There isn't an event to catch when the user de-selects the checkbox.

Expected behavior:

I would expect either the focus event to fire, or a new event be defined when the user de-selects the checkbox

Versions of Angular Tree Component, Angular, Node, affected browser(s) and operating system(s):

Angular: 13.2.5
Tree: 11.0.4
Browser: Chrome, Firefox

[ ] Yes (Assistance will be provided if you need help to submit a pull request)
[ x ] No