Add max-height to comment inputs.

services/web/public/stylesheets/app/editor/review-panel.less

@@ -463,6 +463,7 @@
 		margin-top: 3px;
 		overflow-x: hidden;
 		min-height: 3em;
+		max-height: 400px;
 	}
 
 .rp-icon-delete {