[7.3.1] UHE in File dialog

Here's another place where some defensive programming is needed - see
the new ifNotNil: and comment.

Cheers,
Steve

CommonDialogsFileNameRequest>>refreshParentWindow
        ownerWindow ifNotNil: [:window |
                window windowManager ifNotNil: [:wm |
"windowManager can be nil, if the dialog was started from an
ApplicationModel with a window that has been built but not opened yet:
the Window exists, but it is not yet in any WindowManager (and may never
be, e.g. if we use #allButOpen*)"
                        wm processNonCloseOutstandingEventsFor: window]]