message: Don't show add comment in feed if not desktop.
diff: <div class="-controls" v-if="post && post.status === FiresidePost.STATUS_ACTIVE">
  <app-comment-add-button
  - v-if="showCommentAddButton && !hasDevlogsPerms"
  + v-if="showCommentAddButton && !hasDevlogsPerms && Screen.isDesktop"
  resource="Fireside_Post"
  :resource-id="post.id"
  />
  