DropDownButton updates (#724)

CHANGELOG.md

@@ -16,6 +16,20 @@
   ```
 
   With it, it's also possible to have multiple info about the current open flyout. Sub-menus also have their own flyout instance. To close the current flyout, use `Flyout.of(context).close();`
+- Added option to open `DropDownButton` flyout programatically ([#723](https://github.com/bdlukaa/fluent_ui/issues/723))
+  ```dart
+  final dropdownKey = GlobalKey<DropDownButtonState>();
+
+  DropDownButton(
+    key: dropdownKey,
+    ...
+  );
+
+  dropdownKey.currentState?.open(...); // opens the flyout
+
+  final isOpen = dropdownKey.currentState?.isOpen ?? false; // checks if the flyout is open
+  ```
+- **BREAKING** Removed deprecated memebers: `DropDownButtonItem` and `DropDownButton.buttonStyle` ([#724](https://github.com/bdlukaa/fluent_ui/pull/724))
 
 ## 4.2.0
 

example/lib/screens/inputs/button.dart

@@ -172,7 +172,7 @@ ToggleButton(
             ),
             SizedBox(width: 10.0),
             DropDownButton(
-              title: Icon(FluentIcons.edit_mail, size: 22.0),
+              title: Icon(FluentIcons.mail),
               items: [
                 MenuFlyoutItem(
                   leading: Icon(FluentIcons.send),

lib/src/controls/flyouts/flyout.dart

@@ -444,6 +444,7 @@ typedef FlyoutTransitionBuilder = Widget Function(
   Widget child,
 );
 
+/// Controls the state of a flyout
 class FlyoutController with ChangeNotifier {
   _FlyoutTargetState? _attachState;
   bool _open = false;
@@ -484,17 +485,23 @@ class FlyoutController with ChangeNotifier {
   /// [builder] builds the flyout with the given context. Usually a [FlyoutContent]
   /// is used
   ///
+  /// {@template fluent_ui.flyouts.barrierDismissible}
   /// If [barrierDismissible] is true, tapping outside of the flyout will close
   /// it.
+  /// {@end-template}
   ///
   /// [barrierColor] is the color of the barrier.
   ///
+  /// {@template fluent_ui.flyouts.dismissWithEsc}
   /// When [dismissWithEsc] is true, the flyout can be dismissed by pressing the
   /// ESC key.
+  /// {@end-template}
   ///
+  /// {@template fluent_ui.flyouts.dismissOnPointerMoveAway}
   /// If [dismissOnPointerMoveAway] is enabled, the flyout is dismissed when the
   /// cursor moves away from either the target or the flyout. It's disabled by
   /// default.
+  /// {@end-template}
   ///
   /// [placementMode] describes where the flyout will be placed. Defaults to auto
   ///