video-provider: revert videoListItem max-height change

I did it to force the placeholder to fill the grid, but it turns out it botches Safari and I dont know how to fix it yet

bigbluebutton-html5/imports/ui/components/video-provider/video-list/styles.scss

@@ -40,7 +40,7 @@
   display: flex;
   overflow: hidden;
   width: 100%;
-  height: 100%;
+  max-height: 100%;
 
   &.focused {
     grid-column: 1 / span 2;