shell/window-tracker: Do not filter tracked windows by type
The window-type property may change, and with it the skip-taskbar property that decides whether we consider it "interesting".
As a result we can end up showing untracked window, i.e. one which does not have an associated app.
Cover this case by simply tracking all windows regardless of their type. This won't change the app's running state, as that is solely based on the skip-taskbar property (which is enforced for all previously excluded window types).