Fix API auth for REST (#925)

Author: dnys1

packages/amplify_api/lib/method_channel_api.dart

@@ -278,6 +278,9 @@ class AmplifyAPIMethodChannel extends AmplifyAPI {
     inputsMap['restOptions'] = restOptions.serializeAsMap();
     inputsMap['cancelToken'] = cancelToken;
 
+    // Refresh auth tokens
+    await _authProviderRefresher();
+
     // Attempt switch to proper async
     try {
       final Map<String, dynamic>? data = (await (_channel