The logout greeter theme has a timer that invokes the current action if
no keyboard interaction has taken place.
This cancel on keyboard nav is broken on multiple monitor setups as even
if a user is interacting with one, the timer from another can still
fire.
Fix is via JS singleton library as the timer is very theme specific. I
didn't want to add anything in shutdowndlg.cpp as it would be breaking
layering.
BUG: 394249