[AtModem] Update IndexSSL for correct SSL context (#1386)

Co-authored-by: José Simões <[email protected]>

Author: rikkreeftenberg

devices/AtModem/Http/Sim7672HttpClient.cs

@@ -19,8 +19,8 @@ internal class Sim7672HttpClient : HttpClient
     {
         private const string RootCaFileName = "crt";
 
-        // 1 is MQTT, so let's take 2 for HTTP
-        private const int IndexSSL = 2;
+        // 1 is MQTT, let's take 0 because that sets the correct SSL context ID (the default one). 
+        private const int IndexSSL = 0;
         private ManualResetEvent _httpActionArrived = new ManualResetEvent(false);
         private HttpActionResult _httpActionResult = null;
         private X509Certificate _certAuth;