message: drop video preview max-height to 300px
diff: @@ -17,7 +17,7 @@ limitations under the License.
  span.mx_MVideoBody {
  video.mx_MVideoBody {
  max-width: 100%;
  - height: auto;
  + max-height: 300px;
  border-radius: 4px;
  }
  }
  