The color, opacity, and size to use for the icons that appear in the app bar's actions.
This property should only be used when the actions should be themed differently than the icon that appears in the app bar's leading widget.
If this property is null, then AppBarTheme.actionsIconTheme of ThemeData.appBarTheme is used. If that is also null, then the value of iconTheme is used.
This property is used to configure an AppBar.
final IconThemeData? actionsIconTheme;