message: add z-index to format bar so it appears above status area and reply wrapper
diff: @@ -23,6 +23,9 @@ limitations under the License.
  border-radius: 4px;
  background-color: $message-action-bar-bg-color;
  user-select: none;
  + // equal to z-index of mx_ReplyPreview and mx_RoomView_statusArea (1000)
  + // but as it appears after them in the DOM, will appear on top.
  + z-index: 1000;
  &.mx_MessageComposerFormatBar_shown {
  display: block;
  