### 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

Hi,

My team is trying to support universal linking in our application. Currently, in order to receive a handoff event from the browser, the application needs to listen to `continue-activity` event which provides `type` and `userInfo`. As per the Apple documentation [here](https://developer.apple.com/library/archive/documentation/UserExperience/Conceptual/Handoff/AdoptingHandoff/AdoptingHandoff.html#//apple_ref/doc/uid/TP40014338-CH2-SW10), the browser sends the app an `NSUserActivity` object with an `activityType` value of `NSUserActivityTypeBrowsingWeb`. The `webpageURL` property contains the URL the user was visiting, while the `userInfo` dictionary is empty. 

To provide a smooth handoff our application needs to know the URL the user is navigating from. Therefore, it would be great if the `webpageURL` parameter is exposed in `continue-activity` event. 


### Proposed Solution

The `NSUserActivity` object contains the `webpageURL` property which is set during the handoff process. 
I don't have any experience with Objective C but I believe the `webpageURL` property on the `userActivity` object can be allowed to pass [here](https://github.com/electron/electron/blob/da2baabb96161ea08a15820451f9374d63b4d678/shell/browser/mac/electron_application_delegate.mm#L161) to make it accessible.
https://github.com/electron/electron/blob/da2baabb96161ea08a15820451f9374d63b4d678/shell/browser/mac/electron_application_delegate.mm#L161


### Alternatives Considered

-

### Additional Information

The application needs to know the URL from where the user is navigating to provide a customized handoff experience. 
shell/browser/api/electron_api_app.cc
gin_helper::ErrorThrower(isolate).ThrowError(
        "Must pass valid certificate object.");
    return;
  }
  std::string data;
  if (!cert_data.Get("data", &data))
    return;
  auto certs = net::X509Certificate::CreateCertificateListFromBytes(
      base::as_bytes(base::make_span(data.c_str(), data.size())),
      net::X509Certificate::FORMAT_AUTO);
  if (!certs.empty()) {
    scoped_refptr<net::X509Certificate> cert(certs[0].get());
    for (auto& identity : *identities) {
      scoped_refptr<net::X509Certificate> identity_cert =
          identity->certificate();
      
      
      
      
      if (cert->EqualsExcludingChain(identity_cert.get())) {
        net::ClientCertIdentity::SelfOwningAcquirePrivateKey(
            std::move(identity), base::BindRepeating(&GotPrivateKey, delegate,
                                                     std::move(identity_cert)));
        break;
      }
    }
  }
}
#if defined(USE_NSS_CERTS)
int ImportIntoCertStore(CertificateManagerModel* model, base::Value options) {