refactor: initialize empty fields in CommitTableRequest and error response

Author: Joe-Abraham

src/iceberg/catalog/rest/http_client.cc

@@ -106,6 +106,7 @@ ErrorResponse BuildDefaultErrorResponse(const cpr::Response& response) {
       .type = std::string(kRestExceptionType),
       .message = !response.reason.empty() ? response.reason
                                           : GetStandardReasonPhrase(response.status_code),
+      .stack = {},
   };
 }
 

src/iceberg/catalog/rest/rest_catalog.cc

@@ -365,7 +365,11 @@ Result<std::shared_ptr<Table>> RestCatalog::UpdateTable(
   ICEBERG_ENDPOINT_CHECK(supported_endpoints_, Endpoint::UpdateTable());
   ICEBERG_ASSIGN_OR_RAISE(auto path, paths_->Table(identifier));
 
-  CommitTableRequest request{.identifier = identifier};
+  CommitTableRequest request{
+      .identifier = identifier,
+      .requirements = {},
+      .updates = {},
+  };
   request.requirements.reserve(requirements.size());
   for (const auto& req : requirements) {
     request.requirements.push_back(req->Clone());