Bug: VST3PluginTestHost on Windows does not call checkSizeConstraint upon snap-to-edge

Bug report: The plug-in test host does not call CPluginView::checkSizeConstraint when a plug-in window is resized using Windows’ snap-to-edge functionality. This leads to a plug-in’s window not matching its content aspect ratio even when it has correctly implemented size contraints.

Returning kResultFalse from canResize can work around this, but is not a good solution for when VSTGUI_LIVE_EDITING is enabled.