PLT-6240: Remove own pinned post from RHS when removed from channel (#6098)

Dispatch REMOVE_POST event after successfully initiating delete post,
others get informed by websocket event and will mark the msg as deleted
but not delete from RHS.

webapp/actions/post_actions.jsx

@@ -11,6 +11,7 @@ import {loadStatusesForChannel} from 'actions/status_actions.jsx';
 import {loadNewDMIfNeeded, loadNewGMIfNeeded} from 'actions/user_actions.jsx';
 import {trackEvent} from 'actions/diagnostics_actions.jsx';
 import {sendDesktopNotification} from 'actions/notification_actions.jsx';
+import * as GlobalActions from 'actions/global_actions.jsx';
 
 import Client from 'client/web_client.jsx';
 import * as AsyncClient from 'utils/async_client.jsx';
@@ -431,11 +432,6 @@ export function updatePost(post, success, isPost) {
         });
 }
 
-export function removePostFromStore(post) {
-    PostStore.removePost(post);
-    PostStore.emitChange();
-}
-
 export function emitEmojiPosted(emoji) {
     AppDispatcher.handleServerAction({
         type: ActionTypes.EMOJI_POSTED,
@@ -448,7 +444,7 @@ export function deletePost(channelId, post, success, error) {
         channelId,
         post.id,
         () => {
-            removePostFromStore(post);
+            GlobalActions.emitRemovePost(post);
             if (post.id === PostStore.getSelectedPostId()) {
                 AppDispatcher.handleServerAction({
                     type: ActionTypes.RECEIVED_POST_SELECTED,