fix creation of auth server metadata url

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

Author: JoTiTu

src/WalletFramework.Oid4Vc/Oid4Vci/Implementations/Oid4VciClientService.cs

@@ -406,21 +406,8 @@ private async Task<AuthorizationServerMetadata> FetchAuthorizationServerMetadata
         Uri credentialIssuer = issuerMetadata.CredentialIssuer;
 
         var authServerUrl = issuerMetadata.AuthorizationServers.Match(
-            servers =>
-            {
-                Uri first = servers.First();
-                return first;
-            },
-            () =>
-            {
-                string result;
-                if (string.IsNullOrWhiteSpace(credentialIssuer.AbsolutePath) || credentialIssuer.AbsolutePath == "/")
-                    result = $"{credentialIssuer.GetLeftPart(UriPartial.Authority)}/.well-known/oauth-authorization-server";
-                else
-                    result = $"{credentialIssuer.GetLeftPart(UriPartial.Authority)}/.well-known/oauth-authorization-server" + credentialIssuer.AbsolutePath.TrimEnd('/');
-
-                return new Uri(result);
-            });
+            servers => CreateAuthorizationServerMetadataUri(servers.First()),
+            () => CreateAuthorizationServerMetadataUri(credentialIssuer));
 
         var getAuthServerResponse = await _httpClient.GetAsync(authServerUrl);
 
@@ -437,4 +424,14 @@ private async Task<AuthorizationServerMetadata> FetchAuthorizationServerMetadata
 
         return authServer;
     }
+    
+    private static Uri CreateAuthorizationServerMetadataUri(Uri authorizationServerUri)
+    {
+        string result;
+        if (string.IsNullOrWhiteSpace(authorizationServerUri.AbsolutePath) || authorizationServerUri.AbsolutePath == "/")
+            result = $"{authorizationServerUri.GetLeftPart(UriPartial.Authority)}/.well-known/oauth-authorization-server";
+        else
+            result = $"{authorizationServerUri.GetLeftPart(UriPartial.Authority)}/.well-known/oauth-authorization-server" + authorizationServerUri.AbsolutePath.TrimEnd('/');
+        return new Uri(result);
+    }
 }