Ignore "Keep plugin windows on top" setting when on wayland (#7901)

Fix a crash that occurs when running under Wayland and when loading a VST
plugin with the option "Keep plugin windows on top when not embedded"
enabled.

src/gui/GuiApplication.cpp

@@ -79,6 +79,11 @@ GuiApplication* GuiApplication::instance()
 	return s_instance;
 }
 
+bool GuiApplication::isWayland()
+{
+	return QGuiApplication::platformName().contains("wayland");
+}
+
 
 
 GuiApplication::GuiApplication()