message: fixed send button click bug on firefox
diff: <button color="primary" mat-icon-button (click)="toggleEmojiPicker()">
  <mat-icon>sentiment_very_satisfied</mat-icon>
  </button>
  - <button color="primary" class="msg-send" mat-icon-button>
  - <mat-icon (click)="postMessage()">send</mat-icon>
  + <button (click)="postMessage()" color="primary" class="msg-send" mat-icon-button>
  + <mat-icon >send</mat-icon>
  </button>
  </div>
  </div>
  