fix(specs): body is not required in multiple batch request (generated)

algolia/api-clients-automation#3454

Co-authored-by: algolia-bot <[email protected]>
Co-authored-by: Kai Welke <[email protected]>

Author: algolia-bot

packages/client_search/lib/src/model/multiple_batch_request.dart

@@ -11,7 +11,7 @@ final class MultipleBatchRequest {
   /// Returns a new [MultipleBatchRequest] instance.
   const MultipleBatchRequest({
     required this.action,
-    required this.body,
+    this.body,
     required this.indexName,
   });
 
@@ -20,7 +20,7 @@ final class MultipleBatchRequest {
 
   /// Operation arguments (varies with specified `action`).
   @JsonKey(name: r'body')
-  final Object body;
+  final Object? body;
 
   /// Index name (case-sensitive).
   @JsonKey(name: r'indexName')