fix client-attestation (#176)

Signed-off-by: Johannes Tuerk <johannes.tuerk@lissi.id>

Author: JoTiTu

src/WalletFramework.Oid4Vc/Oid4Vp/Services/Oid4VpClientService.cs

@@ -205,6 +205,9 @@ from path in field.Path.Select(path => path.TrimStart('$', '.'))
         // TODO: Introduce timeout
         var httpClient = _httpClientFactory.CreateClient();
         httpClient.DefaultRequestHeaders.Clear();
+        if (clientAttestation != null)
+            httpClient.AddClientAttestationPopHeader(clientAttestation);
+        
         var responseMessage = await httpClient.SendAsync(message);
         if (!responseMessage.IsSuccessStatusCode)
         {