PLT-4969 remove Push notifications @ preceeding the username or the user's name (#5629)

app/notification.go

@@ -505,7 +505,7 @@ func sendPushNotification(post *model.Post, user *model.User, channel *model.Cha
 	if *utils.Cfg.EmailSettings.PushNotificationContents == model.FULL_NOTIFICATION {
 		if channel.Type == model.CHANNEL_DIRECT {
 			msg.Category = model.CATEGORY_DM
-			msg.Message = "@" + senderName + ": " + model.ClearMentionTags(post.Message)
+			msg.Message = senderName + ": " + model.ClearMentionTags(post.Message)
 		} else {
 			msg.Message = senderName + userLocale("api.post.send_notifications_and_forget.push_in") + channelName + ": " + model.ClearMentionTags(post.Message)
 		}