minor change

src/Infrastructure/BotSharp.Core/Files/BotSharpFileService.Conversation.cs

@@ -230,7 +230,6 @@ public partial class BotSharpFileService
                 using var fs = new FileStream(Path.Combine(subDir, file.FileName), FileMode.OpenOrCreate);
                 fs.Write(bytes, 0, bytes.Length);
                 fs.Flush();
-                fs.Close();
                 Thread.Sleep(2000);
             }