Make scope required again, otherwise the SDK crashes at init.

Author: ditman

packages/google_identity_services_web/CHANGELOG.md

@@ -31,8 +31,8 @@
       * `enable_granular_consent` to `OverridableTokenClientConfig`.
       * `message` to `GoogleIdentityServicesError`.
     * Fixes:
-      * Assert that `CodeClientConfig.scope` is not empty when creating an instance.
-      * `TokenClientConfig.scope` is no longer `required`.
+      * Assert that `scope` is not empty when used to create `CodeClientConfig`,
+        `TokenClientConfig`, and `OverridableTokenClientConfig` instances.
       * Deprecated `enable_serial_consent`.
 
 ## 0.2.2

packages/google_identity_services_web/lib/src/js_interop/google_accounts_oauth2.dart

@@ -250,7 +250,7 @@ abstract class TokenClientConfig {
     return TokenClientConfig._toJS(
       client_id: client_id.toJS,
       callback: callback.toJS,
-      scope: scope?.join(' ').toJS,
+      scope: scope.join(' ').toJS,
       include_granted_scopes: include_granted_scopes?.toJS,
       prompt: prompt?.toJS,
       enable_granular_consent: enable_granular_consent?.toJS,