feat: add rust safe wrapper certificate match

[johubertj]

Resolved issues:

resolves #5185

Description of changes:

Adds a safe Rust wrapper method, Connection::certificate_match(), to expose the s2n_connection_get_certificate_match C API. Previously, this functionality was only accessible through the low-level FFI

Testing:

Added four unit tests to validate the behavior of the certificate_match Rust wrapper and ensure it correctly reflects the results of the underlying s2n_connection_get_certificate_match C API:

• test_certificate_match_returns_exact_match: Verifies ExactMatch is returned when the client's SNI exactly matches the certificate.

• test_certificate_match_returns_wildcard_match: Verifies WildcardMatch is returned when the SNI matches a wildcard domain in the certificate. (format - *.insect.hexapod)

• test_certificate_match_returns_no_sni_match: Verifies NoSNI is returned when the client does not send an SNI.

• test_certificate_match_returns_no_match: Verifies NoMatch is returned when the SNI does not match any certificate.

These tests provide coverage for all possible enum outcomes and ensure correct integration with the C layer.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[Copilot]

Pull Request Overview

This PR adds a safe Rust wrapper method, Connection::certificate_match(), to expose the underlying C API s2n_connection_get_certificate_match, enabling clients to access certificate matching results through a high-level API.

• Added a new enum (CertSNIMatch) with variants to represent certificate match outcomes and implemented conversion from the low-level enum.
• Introduced the certificate_match() method in the Connection struct with corresponding unit tests to verify its behavior.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
bindings/rust/extended/s2n-tls/src/enums.rs	Added CertSNIMatch enum and its TryFrom conversion for mapping.
bindings/rust/extended/s2n-tls/src/connection.rs	Added certificate_match() method and unit test for certificate matching.

Comments suppressed due to low confidence (1)

bindings/rust/extended/s2n-tls/src/connection.rs:1149

• [nitpick] The variable name 'version' is ambiguous in this context since it represents the certificate match result. Consider renaming it to 'cert_match' for improved clarity.

let mut version = s2n_cert_sni_match::SNI_NO_MATCH;

[jmayclin]

Let's have the test return result types like we do elsewhere, so that we can use ? instead of having all the expect assertions everywhere.