fix incorrect use of getter

platform_device_id/example/lib/main.dart

@@ -27,7 +27,7 @@ class _MyAppState extends State<MyApp> {
     String? deviceId;
     // Platform messages may fail, so we use a try/catch PlatformException.
     try {
-      deviceId = await PlatformDeviceId.getDeviceId;
+      deviceId = await PlatformDeviceId.fetchDeviceId();
     } on PlatformException {
       deviceId = 'Failed to get deviceId.';
     }

platform_device_id/lib/platform_device_id.dart

@@ -11,7 +11,7 @@ class PlatformDeviceId {
   static final DeviceInfoPlugin deviceInfoPlugin = DeviceInfoPlugin();
 
   /// Information derived from `android`-`androidId` or `ios`-`identifierForVendor`
-  static Future<String?> get getDeviceId async {
+  static Future<String?> fetchDeviceId() async {
     String? deviceId;
     try {
       if (kIsWeb) {

platform_device_id/test/platform_device_id_test.dart

@@ -19,7 +19,7 @@ void main() {
   });
 
   test('Get Device ID ', () async {
-    String? deviceID = await PlatformDeviceId.getDeviceId;
+    String? deviceID = await PlatformDeviceId.fetchDeviceId();
     expect(deviceID, '42');
   });
 }

platform_device_id_macos/example/test/widget_test.dart

@@ -20,7 +20,7 @@ void main() {
       find.byWidgetPredicate((Widget widget) =>
           widget is Text &&
           widget.data != null &&
-          widget.data.startsWith('Running on:')),
+          widget.data!.startsWith('Running on:')),
       findsOneWidget,
     );
   });