UI: Ignore all auto URLs for server selection

(cherry picked from commit a36c1d4dd4b07e9b0aa66f286fe52f6f5a8d9e98)

UI/window-basic-main-outputs.cpp

@@ -2426,7 +2426,7 @@ std::shared_future<void> BasicOutputHandler::SetupMultitrackVideo(obs_service_t
 
 	std::optional<std::string> custom_rtmp_url;
 	auto server = obs_data_get_string(settings, "server");
-	if (strcmp(server, "auto") != 0) {
+	if (strncmp(server, "auto", 4) != 0) {
 		custom_rtmp_url = server;
 	}