GUI cancels task POST requests longer than 60 seconds

In ext4 version task posts were not cancelled if request needed more than 60 seconds.
In ext6 this requests were cancelled after 60 seconds in GUI, that results in an unsaved add task window, without any error notice.
After closing task add window and reloading tasks, the new task is in the list with state import.
Possible solution, catch timeout in this case, close window and reload grid.
Will be solved with TRANSLATE-625

This issue still exists. On server side the timeout produces a upload error type 3 (UPLOAD_ERR_PARTIAL).