Update app.py

app.py

@@ -543,5 +543,8 @@ dashboard = vm.Dashboard(
     ),
 )
 
-if __name__ == "__main__":
-    Vizro().build(dashboard).run()
+app = Vizro().build(dashboard)
+server = app.dash.server
+
+if __name__ == "__main__":  
+    app.run()