Toggle TouchBar Visibility Independently

Is it possible to have the Use TouchBar option separate from the usual Visible option. I'd like to use tool-bar to put buttons on my touchbar without any screen real-estate being consumed.

Right now, if I check `Use TouchBar` in the settings while `Visible` is toggled off my touchbar is populated with empty buttons.

Start by reproducing the settings combination where Use TouchBar is enabled and Visible is disabled, then trace the handlers for those two options in the tool-bar package. Done means TouchBar buttons remain available without consuming screen space, and the TouchBar no longer contains empty buttons when the toolbar is hidden.

Written by the indexing model from the issue text.