I still don't know if there is an specific way to install the addons library when registering the addon. But for now, please download the libraries using the pip3 command "pip3 download -b <'your-directory'> " and paste it into the 'site-packages' folder in your blender directory. The libraries are PySide2 and Shiboken2.
After installed, open your blender file, register in your preferences menu, open the sculpt environment, click in mask and then 'Animated Preview'. When you hover the brush the animated gif will pop up.
