Mac: Select All, Cut, Copy and Paste key shortcuts don't work in AA_PluginApplication mode, crash the app

Tl;dr: the QNSView_Menu.mm code should not return YES on respondsToSelector for cut,copy,pase commands IF the application is running in plugin mode, AA_PluginApplication.

Details:

Apps written with Cocoa that have the default Edit menu implemented using NSMenu and NSMenuItem that later add Qt as a plugin will incorrectly show the Edit menu commands available while focus is in a QNSView-based window.

When the user tries to use the keyboard shortcuts for the cut/copy/paste/select all commands, e.g. on a QtQuick TextField, instead of the TextField control handling the commands they get intercepted by the QNSView which attempts to treat them as if coming from a QCocoaMenu/QCocoaNSMenuItem instance.

The code in -[QNSView forwardInvocation] then ends up crashing because it forwards the call to the super class without first checking if it responds to the selector.