message: assign height to MediaBarItem so backdrop can work
diff: <template>
  <div class="media-bar-item" :style="{ width, height }">
  - <a class="-wrapper">
  + <a class="-wrapper" :style="{ height }">
  <slot />
  <app-media-item-backdrop class="-backdrop" :media-item="item.media_item" radius="lg">
  <app-img-responsive
  