Fix open file with Cura

CURA-5203

When open a file that's associated with Cura, dialogs that need to
pop up may not work because QML is still in the middle of initialization,
so we need to wait for QML to finish before doing anything else such
as opening files.

resources/qml/Cura.qml

@@ -855,6 +855,16 @@ UM.MainWindow
         id: askOpenAsProjectOrModelsDialog
     }
 
+    Connections
+    {
+        target: CuraApplication
+        onOpenProjectFile:
+        {
+            askOpenAsProjectOrModelsDialog.fileUrl = project_file;
+            askOpenAsProjectOrModelsDialog.show();
+        }
+    }
+
     EngineLog
     {
         id: engineLog;