Disable MixerScriptsPage of both required flags are not set (#879)

* Disable MixerScriptsPage for 2.5 release builds
Since it doesn't work anyway without LUA=Y

* Only enable tab when both flags set

Author: pfeerick

radio/src/gui/colorlcd/menu_model.cpp

@@ -48,7 +48,7 @@ ModelMenu::ModelMenu():
   addTab(new ModelGVarsPage());
   addTab(new ModelLogicalSwitchesPage());
   addTab(new SpecialFunctionsPage(g_model.customFn));
-#if defined(LUA)
+#if defined(LUA) && defined(LUA_MODEL_SCRIPTS)
   addTab(new ModelMixerScriptsPage());
 #endif
   addTab(new ModelTelemetryPage());