fix(tile-view): stop using border on active-speaker, shadow only

The border changes the tile sizing, due to box-sizing, and that
messes with the video aspect ratio.

css/filmstrip/_tile_view.scss

      * see.
      */
     .active-speaker {
-        border: $thumbnailVideoBorder solid $videoThumbnailSelected;
-        box-shadow: inset 0 0 3px $videoThumbnailSelected,
-        0 0 3px $videoThumbnailSelected;
+        box-shadow: 0 0 5px 3px $videoThumbnailSelected
     }
 
     #filmstripRemoteVideos {
         padding: 100px 0;
 
         .videocontainer {
+            border: 0;
             box-sizing: border-box;
             display: block;
             margin: 5px;