Bug 1095826 - [RTL][Video] Thumbnail images do not appear

Good catch. It would have shifted everything over by .4rem but I quite accidentally left 'position: absolute' in the unwatched css so it wasn't being shifted (and unwatched wasn't participating in the flexbox). Because the unwatched indicator was always on top of the thumbnail, it should not participate in the flexbox and should continue to use absolute positioning. I will make the change to remove it from the flexbox (and will add a comment to explain).