Allow leaflet swipe gesture in titlebars on mobile
A followup from !332 (merged)
Currently we only enable swipes in the content area of the window, but not in titlebar because it would interfere with window dragging. However, this isn't a concern on mobile, and it would make sense to be able to perform the gesture there.
However, AFAIU we don't have a way to know whether we can or can't drag the window on this particular device/environment right now.