Fix #5959: set OnRedirectToIdentityProvider events without overwrite previous settings.

Oqtane.Server/Extensions/OqtaneSiteAuthenticationBuilderExtensions.cs

@@ -129,9 +129,7 @@ namespace Oqtane.Extensions
                     options.Events.OnRemoteFailure = OnRemoteFailure;
                     if (sitesettings.GetValue("ExternalLogin:Parameters", "") != "")
                     {
-                        options.Events = new OAuthEvents
-                        {
-                            OnRedirectToAuthorizationEndpoint = context =>
+                        options.Events.OnRedirectToAuthorizationEndpoint = context =>
                         {
                             var url = context.RedirectUri;
                             foreach (var parameter in sitesettings.GetValue("ExternalLogin:Parameters", "").Split(","))
@@ -140,7 +138,6 @@ namespace Oqtane.Extensions
                             }
                             context.Response.Redirect(url);
                             return Task.FromResult(0);
-                            }
                         };
                     }
                 }