Ignore messages that are in queue for too long

TTSListening.cs

@@ -55,6 +55,12 @@ namespace TwitchChatTTS
                             return;
                         }
 
+                        if (DateTime.UtcNow - group.Timestamp > TimeSpan.FromSeconds(60))
+                        {
+                            _logger.Debug("Ignored message due to being in queue for too long.");
+                            continue;
+                        }
+
                         FetchMasterAudio(group);
                     }
                     catch (COMException e)