MM-12795: remove @ from push notifications (#10298)

* remove @ from push notifications

* prepend @ when display name is set to username

* fix @ in username

* fix username getting prefixed in push notifications

app/notification_push.go

@@ -133,6 +133,10 @@ func (a *App) sendPushNotification(notification *postNotification, user *model.U
 	channelName := notification.GetChannelName(nameFormat, user.Id)
 	senderName := notification.GetSenderName(nameFormat, *cfg.ServiceSettings.EnablePostUsernameOverride)
 
+	if senderName == notification.sender.Username {
+		senderName = "@" + senderName
+	}
+
 	c := a.Srv.PushNotificationsHub.GetGoChannelFromUserId(user.Id)
 	c <- PushNotification{
 		notificationType:   NOTIFICATION_TYPE_MESSAGE,
@@ -155,7 +159,7 @@ func (a *App) getPushNotificationMessage(postMessage string, explicitMention, ch
 		if channelType == model.CHANNEL_DIRECT {
 			return strings.Trim(userLocale("api.post.send_notifications_and_forget.push_image_only"), " ")
 		}
-		return "@" + senderName + userLocale("api.post.send_notifications_and_forget.push_image_only")
+		return senderName + userLocale("api.post.send_notifications_and_forget.push_image_only")
 	}
 
 	contentsConfig := *a.Config().EmailSettings.PushNotificationContents
@@ -164,7 +168,7 @@ func (a *App) getPushNotificationMessage(postMessage string, explicitMention, ch
 		if channelType == model.CHANNEL_DIRECT {
 			return model.ClearMentionTags(postMessage)
 		}
-		return "@" + senderName + ": " + model.ClearMentionTags(postMessage)
+		return senderName + ": " + model.ClearMentionTags(postMessage)
 	}
 
 	if channelType == model.CHANNEL_DIRECT {
@@ -172,22 +176,22 @@ func (a *App) getPushNotificationMessage(postMessage string, explicitMention, ch
 	}
 
 	if channelWideMention {
-		return "@" + senderName + userLocale("api.post.send_notification_and_forget.push_channel_mention")
+		return senderName + userLocale("api.post.send_notification_and_forget.push_channel_mention")
 	}
 
 	if explicitMention {
-		return "@" + senderName + userLocale("api.post.send_notifications_and_forget.push_explicit_mention")
+		return senderName + userLocale("api.post.send_notifications_and_forget.push_explicit_mention")
 	}
 
 	if replyToThreadType == THREAD_ROOT {
-		return "@" + senderName + userLocale("api.post.send_notification_and_forget.push_comment_on_post")
+		return senderName + userLocale("api.post.send_notification_and_forget.push_comment_on_post")
 	}
 
 	if replyToThreadType == THREAD_ANY {
-		return "@" + senderName + userLocale("api.post.send_notification_and_forget.push_comment_on_thread")
+		return senderName + userLocale("api.post.send_notification_and_forget.push_comment_on_thread")
 	}
 
-	return "@" + senderName + userLocale("api.post.send_notifications_and_forget.push_general_message")
+	return senderName + userLocale("api.post.send_notifications_and_forget.push_general_message")
 }
 
 func (a *App) ClearPushNotificationSync(currentSessionId, userId, channelId string) {