Clear joined channels of TwitchChatConnector on stop

If the channels aren't cleared and the connector is restarted multiple times
it won't join into any channels that the connector has joined before the
restart because it still thinks it has joined them already

Author: hlxid

src/main/scala/org/codeoverflow/chatoverflow/requirement/service/twitch/chat/TwitchChatConnector.scala

@@ -124,6 +124,7 @@ class TwitchChatConnector(override val sourceIdentifier: String) extends Connect
     bot.sendIRC().quitServer()
     bot.close()
     status = None
+    channels.clear()
     true
   }
 }