Fix KeyNotFoundException on HttpRequestLatencyListener.OnEventWritten for uknown event sources#6821

dariusclay merged 3 commits intodotnet:maindotnet/extensions:mainfrom

ssmelov:fix_httprequestlatencylistener_oneventwritten_for_unknown_eventsssmelov/extensions:fix_httprequestlatencylistener_oneventwritten_for_unknown_eventsCopy head branch name to clipboard