retry_policy: verbose logging for io errors

[thewisenerd]

may contain information necessary for triaging the issue.

spent waay too much time debugging an issue where ca-certificates was not installed, here's an example of how that error looks.

before:

[2024-11-04T21:17:40Z DEBUG azure_core::policies::retry_policies::retry_policy] io error occurred when making request which will be retried: failed to execute `reqwest` request

after:

[2024-11-04T20:52:39Z DEBUG azure_core::policies::retry_policies::retry_policy] io error occurred when making request which will be retried: Error { context: Full(Custom { kind: Io, error: reqwest::Error { kind: Request, url: "REDACTED", source: hyper_util::client::legacy::Error(Connect, Ssl(Error { code: ErrorCode(1), cause: Some(Ssl(ErrorStack([Error { code: 167772294, library: "SSL routines", function: "tls_post_process_server_certificate", reason: "certificate verify failed", file: "../ssl/statem/statem_clnt.c", line: 1889 }]))) }, X509VerifyResult { code: 20, error: "unable to get local issuer certificate" })) } }, "failed to execute `reqwest` request") }

[heaths]

Given this is limited to an IO error, it seems unlikely PII would be leaked any more than it could be now for other error types e.g., our own HttpError.

I will merge this, but please keep in mind that we have no plans to release any new versions of this unsupported library. We are working on supported versions in main so see main's README.md for details.

See https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html for options to override crates.io to pull down this version.