Fix remaining obsolete X509Certificate usage and invalid LoadPkcs12 overloads

Co-authored-by: BrennanConroy <[email protected]>

Author: Copilot

src/Servers/Kestrel/samples/WebTransportInteractiveSampleApp/Program.cs

@@ -192,7 +192,7 @@ static X509Certificate2 GenerateManualCertificate()
     req.CertificateExtensions.Add(sanBuilder.Build());
     // Sign
     using var crt = req.CreateSelfSigned(now, now.AddDays(14)); // 14 days is the max duration of a certificate for this
-    cert = X509CertificateLoader.LoadPkcs12(crt.Export(X509ContentType.Pfx));
+    cert = X509CertificateLoader.LoadPkcs12(crt.Export(X509ContentType.Pfx), password: null);
 
     // Save
     store.Add(cert);

src/Servers/Kestrel/samples/WebTransportSampleApp/Program.cs

@@ -78,7 +78,7 @@ static X509Certificate2 GenerateManualCertificate()
         req.CertificateExtensions.Add(sanBuilder.Build());
         // Sign
         using var crt = req.CreateSelfSigned(now, now.AddDays(14)); // 14 days is the max duration of a certificate for this
-        cert = X509CertificateLoader.LoadPkcs12(crt.Export(X509ContentType.Pfx));
+        cert = X509CertificateLoader.LoadPkcs12(crt.Export(X509ContentType.Pfx), password: null);
 
         // Save
         store.Add(cert);

src/SignalR/clients/csharp/Client/test/UnitTests/HttpConnectionTests.cs

@@ -91,7 +91,7 @@ public async Task HttpOptionsSetOntoHttpClientHandler()
             return testHttpHandler;
         };
         httpOptions.Cookies.Add(new Cookie("Name", "Value", string.Empty, "fakeuri.org"));
-        var clientCertificate = new X509Certificate(Array.Empty<byte>());
+        var clientCertificate = X509CertificateLoader.LoadCertificate(Array.Empty<byte>());
         httpOptions.ClientCertificates.Add(clientCertificate);
         httpOptions.UseDefaultCredentials = false;
         httpOptions.Credentials = Mock.Of<ICredentials>();

src/SignalR/server/SignalR/test/Microsoft.AspNetCore.SignalR.Tests/WebSocketsTransportTests.cs

@@ -31,7 +31,7 @@ public async Task HttpOptionsSetOntoWebSocketOptions()
 
         var httpOptions = new HttpConnectionOptions();
         httpOptions.Cookies.Add(new Cookie("Name", "Value", string.Empty, "fakeuri.org"));
-        var clientCertificate = new X509Certificate(Array.Empty<byte>());
+        var clientCertificate = X509CertificateLoader.LoadCertificate(Array.Empty<byte>());
         httpOptions.ClientCertificates.Add(clientCertificate);
         httpOptions.UseDefaultCredentials = false;
         httpOptions.Credentials = Mock.Of<ICredentials>();