message: Fix the incorrect nesting of MessageActionBar
  mx_MessageActionBar_downloadSpinnerButton::after
diff: @@ -135,12 +135,12 @@ limitations under the License.
  &::after {
  mask-size: 14px;
  mask-image: url('$(res)/img/download.svg');
  + }
  &.mx_MessageActionBar_downloadSpinnerButton::after {
  background-color: transparent; // hide the download icon mask
  }
  }
  - }
  &.mx_MessageActionBar_expandMessageButton::after {
  mask-size: 12px;
  