[Mono.Android] use X509TrustManagerExtensions for `network_security…

…_config.xml` (#9302)

Related to dotnet/runtime#107695

When `<domain-config ...>` is used in `network_security_config.xml`
then all calls to `_internalTrustManager.CheckServerTrusted
(javaChain, authType);` will throw an exception and we will always
pass `SslPolicyErrors.RemoteCertificateChainErrors` to the custom
server certificate validation callback.

To fix this, it is necessary to use hostname-specific certificate
check via `X509TrustManagerExtensions`.

src/Mono.Android/Xamarin.Android.Net/ServerCertificateCustomValidator.cs

@@ -6,6 +6,7 @@
 using System.Security.Cryptography.X509Certificates;
 
 using Android.OS;
+using Android.Net.Http;
 using Android.Runtime;
 using Javax.Net.Ssl;
 
@@ -53,7 +54,8 @@ public void CheckServerTrusted (JavaX509Certificate[] javaChain, string authType
 				var sslPolicyErrors = SslPolicyErrors.None;
 
 				try {
-					_internalTrustManager.CheckServerTrusted (javaChain, authType);
+					var trustManagerExtensions = new X509TrustManagerExtensions (_internalTrustManager);
+					trustManagerExtensions.CheckServerTrusted (javaChain, authType, _request.RequestUri.Host);
 				} catch (JavaCertificateException) {
 					sslPolicyErrors |= SslPolicyErrors.RemoteCertificateChainErrors;
 				}