[Notifications] Also check transient parent for whether it's a dialog
In case a context menu is opened, we want to check the dialog it came from. This fixes the case of notifications dancing around when opening a context menu in System Tray but does not fix the case when opening a context menu in the notification itself since there it cannot know that the still open System Tray popup is the one we should evade and not the popup with the menu in it.
it technically fixes the bug as reported but I know that it doesn't work when the context menu emenates from the notification itself. Still a slight improvement over the status quo :)