remove trial codes in _comment_growi.scss

resource/styles/scss/_comment_growi.scss

@@ -100,11 +100,6 @@
         transition: height 0.2s ease-out;
         height: 180px;
       }
-
-    // formPreview
-    .comment-form-preview{
-      height: 80px;
-    }
     }
   }
 }