Revert "add helper method to add ephemeral messages; also switch 'delete mess…"

web/react/utils/utils.jsx

@@ -1254,8 +1254,3 @@ export function isFeatureEnabled(feature) {
 export function isSystemMessage(post) {
     return post.type && (post.type.lastIndexOf(Constants.SYSTEM_MESSAGE_PREFIX) === 0);
 }
-
-// convenience method to dispatch an event in JS' next event cycle
-export function defer(fn) {
-    setTimeout(fn, 0);
-}