Não volto para tela principal

Fiz o codigo aqui, porem não aparece a seta para que eu possa voltar a tela principal Versão flutter 2.5.2

class Dashboard extends StatelessWidget {
  const Dashboard({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Dashboard'),
      ),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Padding(
            padding: const EdgeInsets.all(8.0),
            child: Image.asset('images/bytebank_logo.png'),
          ),
          Padding(
            padding: const EdgeInsets.all(8.0),
            child: Material(
              color: Theme.of(context).primaryColor,
              child: InkWell(
                onTap: () {
                  Navigator.of(context).push(
                    MaterialPageRoute(
                      builder: (context) => const ContactsList(),
                    ),
                  );
                },
                child: Container(
                  padding: const EdgeInsets.all(8.0),
                  height: 100,
                  width: 150,
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: const [
                      Icon(
                        Icons.people,
                        color: Colors.white,
                        size: 24.0,
                      ),
                      Text(
                        'Contacts',
                        style: TextStyle(color: Colors.white, fontSize: 16.0),
                      ),
                    ],
                  ),
                ),
              ),
            ),
          )
        ],
      ),
    );
  }
}