Merge pull request #25064 from nvartolomei/nv/cst-gcp-unknown-codes

cloud_storage_clients: skip lexical_cast on empty strings

Author: nvartolomei

src/v/cloud_storage_clients/s3_error.cc

@@ -420,7 +420,9 @@ rest_error_response::rest_error_response(
   std::string_view message,
   std::string_view request_id,
   std::string_view resource)
-  : _code(boost::lexical_cast<s3_error_code>(code))
+  : _code(
+      code.empty() ? s3_error_code::_unknown
+                   : boost::lexical_cast<s3_error_code>(code))
   , _code_str(code)
   , _message(message)
   , _request_id(request_id)