multi-delete: Avoid empty Delete tag in the response (#13725)

When removing an object fails, such as when it is WORM protected, a
wrong <Delete> will still be in the response. This commit fixes it.

cmd/api-response.go

@@ -724,9 +724,6 @@ func generateMultiDeleteResponse(quiet bool, deletedObjects []DeletedObject, err
 	if !quiet {
 		deleteResp.DeletedObjects = deletedObjects
 	}
-	if len(errs) == len(deletedObjects) {
-		deleteResp.DeletedObjects = nil
-	}
 	deleteResp.Errors = errs
 	return deleteResp
 }