Fix: Restart was triggered before all website data was sent

This led to the effect that e.g. the confirmation messages where  not shown.

It is somehow related to ESPAsyncWebServer 3.3.0

include/WebApi_firmware.h

@@ -6,13 +6,9 @@
 
 class WebApiFirmwareClass {
 public:
-    WebApiFirmwareClass();
     void init(AsyncWebServer& server, Scheduler& scheduler);
 
 private:
     void onFirmwareUpdateFinish(AsyncWebServerRequest* request);
     void onFirmwareUpdateUpload(AsyncWebServerRequest* request, String filename, size_t index, uint8_t* data, size_t len, bool final);
-
-    Task _rebootTask;
-    void rebootTaskCb();
 };