Hi @BJCarl,
I don't know of a way to disable that option easily. It could certainly be possible to come up with some custom CSS/JavaScript to try to handle that task, but those buttons appear in so many places that the code may get overly complex and is always subject to break when Instructure makes updates.
As a Canvas admin myself, I'm curious as to why you want to hide that button. There are some instances where audio/visual comments are really beneficial for both faculty and students (though I'm sure there is some of the opposite too).
Look forward to hearing back from you!
-Chris