[BUG] Potential authorization issue with Confidential Ledger

Library name and version

Azure.Security.ConfidentialLedger 1.0.0-beta.2

Describe the bug

• Not able to use the certificate based authentication method for authenticating with the Azure Confidential Ledger data plane APIs
• ConfidentialLedgerClient class’s constructor expects TokenCredentials to be not null. Only one should be needed as Authentication can be done via either Certificate or AAD
• ConfidentialLedgerClient seems to validate TokenCredential Paramter to ensure that its not null… but if the client code chooses to use cert based authentication and not rely on TokenCredentials - it throws an error

Expected behavior

• Should be able to use either TokenCredentials or Certificate based credentials

Actual behavior

• Not able to use either TokenCredentials or Certificate based credentials. Code expects both.

Reproduction Steps

Run the below code where the TokenCredentials is not present.

private static void SDKClient(StringContent request, HttpClientHandler handler)
{
    try
    {
        var options = new ConfidentialLedgerClientOptions { Transport = new HttpClientTransport(handler) };
        var ledgerClient = new ConfidentialLedgerClient(new Uri(_ledgerURI), null, options);
        RequestContent requestContent = RequestContent.Create(request);
        var responseForPost = ledgerClient.PostLedgerEntry(requestContent);
        Console.WriteLine(responseForPost.Content);
    }
    catch (HttpRequestException e)
    {
        Console.WriteLine("\nException Caught!");
        Console.WriteLine("Message :{0} ", e.Message);
    }
}

Environment

No response

[christothes]

tracking this in #28147

[rajdhandus]

thanks! this seems to be available in Python SDK

https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/core/azure-core/README.md?plain=1#L181

https://github.com/Azure/azure-sdk-for-python/blob/main/sdk/confidentialledger/azure-confidentialledger/README.md?plain=1#L237

https://azuresdkdocs.blob.core.windows.net/$web/python/azure-confidentialledger/latest/azure.confidentialledger.html?highlight=certificatecredential#azure.confidentialledger.ConfidentialLedgerCertificateCredential