v1.7.1: fix send audio (#771)

* screen -> display

* Add AUDIO_CODEC_DEFAULT_MIC_GAIN

* WebRTC -> NSNet

* fix: send audio priority

main/application.cc

@@ -719,6 +719,9 @@ void Application::Schedule(std::function<void()> callback) {
 // If other tasks need to access the websocket or chat state,
 // they should use Schedule to call this function
 void Application::MainEventLoop() {
+    // Raise the priority of the main event loop to avoid being interrupted by background tasks (which has priority 2)
+    vTaskPrioritySet(NULL, 3);
+
     while (true) {
         auto bits = xEventGroupWaitBits(event_group_, SCHEDULE_EVENT | SEND_AUDIO_EVENT, pdTRUE, pdFALSE, portMAX_DELAY);