introduce system status in WebUI for easier monitoring of tasks

src/web/WebSchedulerService.cpp

@@ -523,7 +523,7 @@ void WebSchedulerService::loop() {
 void WebSchedulerService::scheduler_task(void * pvParameters) {
     while (1) {
         delay(10); // no need to hurry
-        if (!EMSESP::system_.upload_isrunning()) {
+        if (EMSESP::system_.systemStatus() == SYSTEM_STATUS::SYSTEM_STATUS_NORMAL) {
             EMSESP::webSchedulerService.loop();
         }
     }