Describe the bug
If i export a kubeconfig from Rancher there are three certificates present in the certificate-authority-data.

SetClusterDetails in KubernetesClientConfiguration.ConfigFile.cs uses X509CertificateLoader.LoadCertificate to load the certificate, but that does not support certificate collections. Therefore only the first certificate is loaded and the other two are lost and not added to SslCaCerts.

Kubernetes C# SDK Client Version
18.0.5

Dotnet Runtime Version
.NET 9.0+

To Reproduce
Load a kubeconfig file with more than one certificate. SslCaCerts will only contain the first one.

Expected behavior
All certificates are loaded.

Potential fix
X509Certificate2Collection.ImportFromPem imports a collection of PEM certificates and could be a potential fix. At least thats what we do as a workaround for now:

// Import all Certificates
var certData = kubernetesConfiguration.Clusters.FirstOrDefault()?.ClusterEndpoint?.CertificateAuthorityData;

if (!string.IsNullOrWhiteSpace(certData))
{
    var collection = new X509Certificate2Collection();
    var pemText = Encoding.UTF8.GetString(Convert.FromBase64String(certData));
    collection.ImportFromPem(pemText);

    kubernetesClientConfig.SslCaCerts = collection;
}