The document viewer doesn’t display animations from uploaded PowerPoint documents.
There are, however, three alternatives.
Host the presentation
You can upload the PowerPoint file on Google Slides or OneDrive.
Save as a video
You can export the Powerpoint file as a video, then add the video to the course.
See also: Use Screencast-O-Matic for content creation.
Convert into a Genially
You can convert a PowerPoint document into a Genially, then add the embed code to the course.