x11: Don't create decoration input extent window when running on Wayland

Input redirection takes care of handling resize only borders and
relevant event handling code in X11Client has been disabled for a while.

src/x11client.cpp

@@ -1043,6 +1043,10 @@ void X11Client::updateInputWindow()
     if (!Xcb::Extensions::self()->isShapeInputAvailable())
         return;
 
+    if (kwinApp()->operationMode() != Application::OperationModeX11) {
+        return;
+    }
+
     QRegion region;
 
     if (!noBorder() && isDecorated()) {