Fixed two music bot hangups

MusicBot/src/MusicPlayer.cpp

@@ -30,9 +30,12 @@ void AbstractMusicPlayer::unregisterEventHandler(const std::string& string) {
 }
 
 void AbstractMusicPlayer::fireEvent(MusicEvent event) {
-    std::lock_guard lock(this->eventLock);
-    auto listCopy = this->eventHandlers; //Copy for remove while fire
-    for(const auto& entry : listCopy)
+    decltype(this->eventHandlers) handlers{};
+    {
+        std::lock_guard lock(this->eventLock);
+        handlers = this->eventHandlers; //Copy for remove while fire
+    }
+    for(const auto& entry : handlers)
         entry.second(event);
 }