First pass at the new video tile designs

Here, I've begun updating the styles of video tiles to match the new designs. Not yet updated: the local volume option is supposed to go inside an overflow menu now, but I haven't gotten to that yet.

To make the outlines on hovered / speaking tiles show up properly, I have to remove the usePageFocusStyle hack, which was preventing CSS outlines from being used for anything other than focus rings. I honestly can't tell what problem it was solving in the first place: focus rings still appear to behave as expected throughout the application.

src/video-grid/NewVideoGrid.tsx

@@ -178,7 +178,7 @@ export function NewVideoGrid<T>({
       from: ({ x, y, width, height }: Tile<T>) => ({
         opacity: 0,
         scale: 0,
-        shadow: 1,
+        shadow: 0,
         shadowSpread: 0,
         zIndex: 1,
         x,
@@ -221,7 +221,7 @@ export function NewVideoGrid<T>({
           ? {
               scale: 1,
               zIndex: 1,
-              shadow: 1,
+              shadow: 0,
               x: tile.x,
               y: tile.y,
               width: tile.width,