[Runner]Fix network errors when checking for updates (#26742)

* General: re-implementing network error handling

* Remove unreferenced dead code

* Minor modification in the update procedure. Removing the code part which updates the UI before the real check on new version. UI will be updated after the real check is done.

src/common/updating/updateState.h

@@ -12,7 +12,8 @@ struct UpdateState
         upToDate = 0,
         errorDownloading = 1,
         readyToDownload = 2,
-        readyToInstall = 3
+        readyToInstall = 3,
+        networkError = 4
     } state = upToDate;
     std::wstring releasePageUrl;
     std::optional<std::time_t> githubUpdateLastCheckedDate;