Masking is still valid, but object movies plugin is pointless now as Simon internally implemented it a while back as a component - would be nice if he internally implemented masking too.
It's probably not the best of ideas to use that action part like that. It's more meant for changing to the main menu & back, but even then I don't think it's the best of ideas to use. If you optimize your game & use webp image format for your images & animations, then the game should load & run scenes nice & fast & smooth on most devices without needing to clog up the available VRAM.
Anyway, it's just a warning message & it shouldn't affect the game, but you could just install them again if it bothers you that it's getting printed to the log or install & try deactivating them instead of fully removing them.