Check for stopped propagation before showing close dialog

Various VE elements use escape to perform tasks. Particularly
difficult are OOUI dialogs which listen to the document and thus
fire after this target's listener, so defer and check if the
event was previously stopped.

Bug: T78201
Change-Id: Ie335f199766923833588202626c3af8e4cbcb9b5
Update VE core submodule to master (6103755)

New changes:
cd56662 Move ve.init.Target#destroy to a place where it actually ends up existing
91347cb Factor out event handler binding in ve.init.Target
489cd55 Death to isolation
4597c9a Stop propagation of events after handling trigger keys
ea35d23 Non-DOM-modifying selection
6103755 Fix demo CSS hack broken by OOUI change

Change-Id: I087f2fa6a46742f39e7f25ffe5432465ab328182
Merge "Check for stopped propagation before showing close dialog"
Merge "Update VE core submodule to master (6103755)"