I did a screen capture video. I dragged it into a timeline. There's an audio track attached to the file. I don't need it, but I don't see a way to get rid of it either. None of my software seems to have that ability.
Please note that what @Gid proposes doesn't remove the audio from the original file as any video editor will be non destructive to the original files. It will just remove the audio from any export. Equally you could just open the audio mixer and turn the volume slider all the way off.