[google_sign_in] Correct method channel clearAuthCache declaration (#5787)

During the NNBD migrations, the platform interface version was correctly converted to `required String token`, but the implementation was instead changed to `String? token`. Since accepting a nullable type is a valid override of accepting a non-nullable type it still compiled, but added unnecessary force unwrapping to the implementations. This cleans up the default method channel implementation declaration to match the platform interface.

Fixes flutter/flutter#129717

Author: stuartmorgan-g

packages/google_sign_in/google_sign_in_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.4.4
+
+* Updates `clearAuthCache` override to match base class declaration.
+
 ## 2.4.3
 
 * Updates minimum supported SDK version to Flutter 3.10/Dart 3.0.

packages/google_sign_in/google_sign_in_platform_interface/lib/src/method_channel_google_sign_in.dart

@@ -84,7 +84,7 @@ class MethodChannelGoogleSignIn extends GoogleSignInPlatform {
   }
 
   @override
-  Future<void> clearAuthCache({String? token}) {
+  Future<void> clearAuthCache({required String token}) {
     return channel.invokeMethod<void>(
       'clearAuthCache',
       <String, String?>{'token': token},

packages/google_sign_in/google_sign_in_platform_interface/pubspec.yaml

@@ -4,7 +4,7 @@ repository: https://github.com/flutter/packages/tree/main/packages/google_sign_i
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+google_sign_in%22
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 2.4.3
+version: 2.4.4
 
 environment:
   sdk: ">=3.0.0 <4.0.0"