### Summary of Most Important Changes

The code changes primarily focus on improving the robustness and user feedback of the `TwitchHandler.cs` file, specifically in handling track fetching and adding tracks to a playlist. Additionally, the version number in `AssemblyInfo.cs` has been incremented.

### List of Changes

1. **Version Number Update**:
   - The version numbers in `AssemblyInfo.cs` have been updated from `1.6.4.5` to `1.6.4.6`.
   - **Reference**: `AssemblyInfo.cs`

2. **Null Check for Track Object**:
   - A null check for the `track` object has been added after fetching the track using `SpotifyApiHandler.GetTrack(trackId)`. If the track is null, a chat message indicating no track was found is sent, and the function returns early.
   - **Reference**: `TwitchHandler.cs`

3. **Success Response Message**:
   - A line has been added to send a chat message with the success response after adding the track to the playlist and before uploading it to the queue.
   - **Reference**: `TwitchHandler.cs`

4. **Handling Spotify Availability in Russia**:
   - A fix has been added to handle the case where Spotify is not available in Russia. If the track has an error with status 403, a specific message "Track has been added to the queue." is returned.
   - **Reference**: `TwitchHandler.cs`

Songify Slim/Properties/AssemblyInfo.cs

@@ -50,7 +50,7 @@
 // You can specify all the values or you can default the Build and Revision Numbers
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("1.6.4.5")]
-[assembly: AssemblyFileVersion("1.6.4.5")]
+[assembly: AssemblyVersion("1.6.4.6")]
+[assembly: AssemblyFileVersion("1.6.4.6")]
 [assembly: NeutralResourcesLanguage("en")]
 [assembly: Guid("442379e3-32d8-42d1-ab09-cba229672453")]

Songify Slim/Util/Songify/TwitchHandler.cs

@@ -606,6 +606,7 @@ private static async void AddSong(string trackId, OnMessageReceivedArgs e)
 
             FullTrack track = await SpotifyApiHandler.GetTrack(trackId);
 
+
             if (track == null)
             {
                 SendChatMessage(Settings.Settings.TwChannel, CreateNoTrackFoundResponse(e));
@@ -667,6 +668,7 @@ private static async void AddSong(string trackId, OnMessageReceivedArgs e)
                 await AddToPlaylist(track.Id);
 
             response = CreateSuccessResponse(track, e.ChatMessage.DisplayName);
+
             SendChatMessage(e.ChatMessage.Channel, response);
             await UploadToQueue(track, e.ChatMessage.DisplayName);
             GlobalObjects.QueueUpdateQueueWindow();
@@ -1755,6 +1757,11 @@ private static string CreateSuccessResponse(FullTrack track, string displayName)
             string response = Settings.Settings.BotRespSuccess;
             string artists = "";
             string singleArtist = "";
+
+            //Fix for russia where Spotify is not available
+            if (track.HasError() && track.Error.Status == 403)
+                return "Track has been added to the queue.";
+
             try
             {
                 artists = string.Join(", ", track.Artists.Select(o => o.Name).ToList());