debug mode added for memory testing

src/activities/settings/OtaUpdateActivity.cpp

@@ -90,6 +90,7 @@ void OtaUpdateActivity::onExit() {
   if (displayTaskHandle) {
     vTaskDelete(displayTaskHandle);
     displayTaskHandle = nullptr;
+    vTaskDelay(10 / portTICK_PERIOD_MS);  // Let idle task free stack
   }
   vSemaphoreDelete(renderingMutex);
   renderingMutex = nullptr;