message: fix sending of attachment only message
diff: @@ -431,7 +431,7 @@ export default class ChatWindow {
  private onInputKeyPress = (ev) => {
  let message: string = <string>$(ev.target).val();
  - if (ev.which !== ENTER_KEY || ev.shiftKey || !message) {
  + if (ev.which !== ENTER_KEY || ev.shiftKey || (!message && !this.attachmentDeposition)) {
  return;
  }
  