[ATSPI] do not make window hidden when bridge removes top level window

[ATSPI] do not make window hidden when bridge removes top level window

OnAccessibilityDisabled > RemoveTopLevelWindow > WindowHidden
makes mIsShown become FALSE

After this point, if the Accessibility is Enabled then the Bridge
does not call EmitActivate in ForceUp because mIsShown is FALSE by
RemoveTopLevelWindow > WindowHidden (mentioned above)

I cannot find any reason calling WindowHidden in RemoveTopLevelWindow
Please refer to following patch

ttps://review.tizen.org/gerrit/#/c/platform/core/uifw/dali-adaptor/+/264762/8/dali/internal/accessibility/bridge/bridge-base.cpp@277

Change-Id: I6ebf2e4b94ff00867950047591539e8c8bc96c3a