PLT-7502 fixing clearing of push notifications for iOS (#7429)

* PLT-7502 fixing clearing of push notificaitons for iOS

* PLT-7502 fixing clearing of push notificaitons for iOS

app/notification.go

@@ -649,10 +649,18 @@ func (a *App) sendPushNotification(post *model.Post, user *model.User, channel *
 	return nil
 }
 
-func (a *App) ClearPushNotification(userId string, channelId string) *model.AppError {
+func (a *App) ClearPushNotification(userId string, channelId string) {
+	go func() {
+		// Sleep is to allow the read replicas a chance to fully sync
+		// the unread count for sending an accurate count.
+		// Delaying a little doesn't hurt anything and is cheaper than
+		// attempting to read from master.
+		time.Sleep(time.Second * 5)
+
 		sessions, err := a.getMobileAppSessions(userId)
 		if err != nil {
-		return err
+			l4g.Error(err.Error())
+			return
 		}
 
 		msg := model.PushNotification{}
@@ -673,8 +681,7 @@ func (a *App) ClearPushNotification(userId string, channelId string) *model.AppE
 			tmpMessage.SetDeviceIdAndPlatform(session.DeviceId)
 			go a.sendToPushProxy(tmpMessage, session)
 		}
-
+	}()
-	return nil
 }
 
 func (a *App) sendToPushProxy(msg model.PushNotification, session *model.Session) {