actions property Null safety
The (optional) set of actions that are displayed at the bottom of the dialog with an OverflowBar.
Typically this is a list of TextButton widgets. It is recommended to set the Text.textAlign to TextAlign.end for the Text within the TextButton, so that buttons whose labels wrap to an extra line align with the overall OverflowBar's alignment within the dialog.
If the title is not null but the content is null, then an extra 20 pixels of padding is added above the OverflowBar to separate the title from the actions.
final List<Widget>? actions;