Use case

Tried to adopt the new Material 3 dialog spec and found that Flutter does not "natively" support it and requires adding unintended widgets (like Column, Icon and SizedBox) in the title parameter to replicate it.

Proposal

Additional parameter/field heroIcon, causing the AlertDialog to adopt the "hero style".

Expected sample code mimicking Material spec render:

AlertDialog(
  heroIcon: Icon(Icons.mobile_friendly),
  title: Text('Dialog with hero icon'),
  content: Text(
    'A dialog is a type of modal window that '
    'appears in front of app content to provide '
    'critical information, or ask for a decision.',
  ),
  actions: [
    TextButton(child: Text("Enabled"), onPressed: () {}),
    TextButton(child: Text("Enabled"), onPressed: () {}),
  ]
),

By observing the Material specs following things should happen:

• title should inherit textAlign: TextAlign.center when a heroIcon is provided.
• heroIcon should use ThemeData.colorScheme.secondary as its color.

As defined by https://m3.material.io/components/dialogs/specs#23e479cf-c5a6-4a8b-87b3-1202d51855ac