Log connection details when request fails

The server error handling logic should log out the connection details that were sent from the client when a request fails.

This will help diagnose connection issues.

The existing error handling logic inside the proxy server does log some of this information, but it only logs it for thrown errors. Some connection issues result in not errors, but HTTP status codes that are not in the 2xx range.

The header white list should be extended to include IAM auth settings.

Locate the proxy server's existing error-handling logic and header whitelist. Compare the thrown-error path with responses returning non-2xx HTTP status codes. Done means failed requests log the client-sent connection details in both cases and the whitelist includes IAM auth settings.

Written by the indexing model from the issue text.