Fix MM53643 (#25683)

* Fix MM53643

* Add test

* Remove unneeded part of a test

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/notification.go

@@ -485,13 +485,6 @@ func (a *App) SendNotifications(c request.CTX, post *model.Post, team *model.Tea
 
 	message := model.NewWebSocketEvent(model.WebsocketEventPosted, "", post.ChannelId, "", nil, "")
 
-	// Note that PreparePostForClient should've already been called by this point
-	postJSON, jsonErr := post.ToJSON()
-	if jsonErr != nil {
-		return nil, errors.Wrapf(jsonErr, "failed to encode post to JSON")
-	}
-	message.Add("post", postJSON)
-
 	message.Add("channel_type", channel.Type)
 	message.Add("channel_display_name", notification.GetChannelName(model.ShowUsername, ""))
 	message.Add("channel_name", channel.Name)
@@ -530,6 +523,13 @@ func (a *App) SendNotifications(c request.CTX, post *model.Post, team *model.Tea
 		return nil, err
 	}
 	if !published {
+		removePermalinkMetadataFromPost(post)
+		postJSON, jsonErr := post.ToJSON()
+		if jsonErr != nil {
+			return nil, errors.Wrapf(jsonErr, "failed to encode post to JSON")
+		}
+		message.Add("post", postJSON)
+
 		a.Publish(message)
 	}