### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Problem Description

We need to load a custom error page when the certificate is invalid but without "isMainFrame" property we don't know when to load the custom error page using webContents.loadURL()

### Proposed Solution

webContents.on("certificate-error", ((event, url, error, certificate, callback, isMainFrame)

### Alternatives Considered

Not sure

### Additional Information

Not sure
shell/browser/api/electron_api_app.cc
Browser::LoginItemSettings options;
  args->GetNext(&options);
  return Browser::Get()->GetLoginItemSettings(options);
}
#if defined(USE_NSS_CERTS)
void App::ImportCertificate(gin_helper::ErrorThrower thrower,
                            base::Value options,
                            net::CompletionOnceCallback callback) {
  if (!options.is_dict()) {
    thrower.ThrowTypeError("Expected options to be an object");
    return;
  }
  auto* browser_context = ElectronBrowserContext::From("", false);
  if (!certificate_manager_model_) {
    CertificateManagerModel::Create(
        browser_context,
        base::BindOnce(&App::OnCertificateManagerModelCreated,
                       base::Unretained(this), std::move(options),
                       std::move(callback)));
    return;
  }
  int rv =
      ImportIntoCertStore(certificate_manager_model_.get(), std::move(options));
  std::move(callback).Run(rv);
}
void App::OnCertificateManagerModelCreated(