FIX: [STUDIO-1575] end dialog with wxID_ABORT on user end session

Change-Id: Ie509b5780a5d11572eadd6dee2fd93903c128c17

src/slic3r/GUI/GUI_App.cpp

@@ -2064,7 +2064,7 @@ bool GUI_App::on_init_inner()
             }
         }
         for (auto d : dialogStack)
-            d->EndModal(wxID_CANCEL);
+            d->EndModal(wxID_ABORT);
     });
 
     std::map<std::string, std::string> extra_headers = get_extra_header();