Ensure rpId property is checked for Authentication requests

[AlexNachbaur]

No description provided.

[Copilot]

Pull Request Overview

Adds support for reading the top-level rpId property for authentication requests and includes a suite of unit tests covering all identifier-selection paths.

• Introduce a check for json["rpId"] in String.relyingPartyIssuer
• Supply new tests for explicit rpId, U2F params, extensions, issuer fallback, and invalid URL cases

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
Tests/OktaIdxAuthTests/RelyingParthIdentifierTests.swift	Added tests for each relying-party identifier scenario
Sources/OktaIdxAuth/Internal/Extensions/URL+WebAuthnExtensions.swift	Added branch to return root rpId for authentication

Comments suppressed due to low confidence (2)

Tests/OktaIdxAuthTests/RelyingParthIdentifierTests.swift:21

• [nitpick] The test name testExplicitChallengeIdentifier is ambiguous; consider renaming to testExplicitRegistrationIdentifier or testExplicitRelyingPartyIdFromRP for clarity.

    func testExplicitChallengeIdentifier() throws {

Tests/OktaIdxAuthTests/RelyingParthIdentifierTests.swift:36

• Consider adding a test where both rpId and u2fParams are present to verify that rpId takes precedence over u2fParams as implemented.

    func testExplicitAuthenticationIdentifier() throws {