Take away an motion created by a Gravity Varieties add-on

I am utilizing Gravity Varieties Person Registration add-on and must take away the motion that embody the activate web page.

Within the add-on, the hook is known as like this:

add_action( 'wp',        array( $this, 'maybe_activate_user' ) );

That is added inside a public perform referred to as init(), a technique from GF_User_Registration class.

What I attempted:

add_action('init', perform () {
    remove_action('wp', ['GF_User_Registration', 'maybe_activate_user']);
});