I have a docusaurus as front for my company website.
And I'm wondering, how to track clicks on the link to the login form in the administrator's page.

This link is in the siteconfig.js:

```js
headerLinks: [
    {href: 'https://demo.multifactor.ru', label: 'Demo'},
    {doc: 'intro', label: 'Documentation'},
    {doc: 'api', label: 'API'},
    {href: '/login', label: 'Login'}
  ],

```

I've tried to add custom tag, like in the example below, but docusaurus ignore this construction

```js
headerLinks: [
    {href: 'https://demo.multifactor.ru', label: 'Demo'},
    {doc: 'intro', label: 'Documentation'},
    {doc: 'api', label: 'API'},
    {href: '/login', label: 'Login', onClick: 'ga (‘send’, ‘event’, ‘submit’, ‘login_link’);'}
  ],

```

does anybody has ideas about how to do this?