Support distination URL with "?" like a Google Suite SSO URL https://accounts.google.com/o/saml2/idp?idpid=XXXXXXXX

Author: Revsgaard

src/ITfoxtec.Identity.Saml2/Bindings/Saml2RedirectBinding.cs

@@ -35,7 +35,7 @@ protected override Saml2RedirectBinding BindInternal(Saml2Request saml2RequestRe
                 requestQueryString = SigneQueryString(requestQueryString, saml2RequestResponse.Config.SigningCertificate);
             }
 
-            RedirectLocation = new Uri(string.Join("?", saml2RequestResponse.Destination.OriginalString, requestQueryString));
+            RedirectLocation = new Uri(string.Join(saml2RequestResponse.Destination.OriginalString.Contains('?') ? "&" : "?", saml2RequestResponse.Destination.OriginalString, requestQueryString));
 
             return this;
         }