Fix CI build for updated Auth0 client

[Copilot]

The CI build failed after Auth0.AuthenticationApi introduced two new IAuthenticationApiClient methods. The caching decorator no longer implemented the updated interface.

• Auth0 compatibility
  • Added passthrough implementations for:
    • TokenExchangeTokenRequest
    • FederatedConnectionAccessTokenRequest
  • Added XML documentation for both public methods.

public async Task<AccessTokenResponse> GetTokenAsync(
    TokenExchangeTokenRequest request,
    CancellationToken cancellationToken = default)
{
    return await _inner.GetTokenAsync(request, cancellationToken)
        .ConfigureAwait(false);
}