[camera_android] Removes usage of _ambiguate method in example (flutter#4924)

Since the minimum Flutter version for this package is +3.0, we can remove the `_ambiguate` method.

Part of flutter/flutter#111841

Author: nilsreichardt

packages/camera/camera_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.10.8+9
+
+* Removes usage of `_ambiguate` method in example.
+
 ## 0.10.8+8
 
 * Adds pub topics to package metadata.

packages/camera/camera_android/example/lib/main.dart

@@ -75,7 +75,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
   @override
   void initState() {
     super.initState();
-    _ambiguate(WidgetsBinding.instance)?.addObserver(this);
+    WidgetsBinding.instance.addObserver(this);
 
     _flashModeControlRowAnimationController = AnimationController(
       duration: const Duration(milliseconds: 300),
@@ -105,7 +105,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
 
   @override
   void dispose() {
-    _ambiguate(WidgetsBinding.instance)?.removeObserver(this);
+    WidgetsBinding.instance.removeObserver(this);
     _flashModeControlRowAnimationController.dispose();
     _exposureModeControlRowAnimationController.dispose();
     super.dispose();
@@ -580,7 +580,7 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
     }
 
     if (_cameras.isEmpty) {
-      _ambiguate(SchedulerBinding.instance)?.addPostFrameCallback((_) async {
+      SchedulerBinding.instance.addPostFrameCallback((_) async {
         showInSnackBar('No camera found.');
       });
       return const Text('None');
@@ -1075,9 +1075,3 @@ Future<void> main() async {
   }
   runApp(const CameraApp());
 }
-
-/// This allows a value of type T or T? to be treated as a value of type T?.
-///
-/// We use this so that APIs that have become non-nullable can still be used
-/// with `!` and `?` on the stable branch.
-T? _ambiguate<T>(T? value) => value;

packages/camera/camera_android/pubspec.yaml

@@ -3,7 +3,7 @@ description: Android implementation of the camera plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
 
-version: 0.10.8+8
+version: 0.10.8+9
 
 environment:
   sdk: ">=2.19.0 <4.0.0"