Prevent Ghost users from seeing a prompt to upgrade to a paid plan when there isn't a paid plan.

Hide upgrade bug

<!-- Thanks to Ghost user Akshay (https://akshaykhot.com/) for this code snippet. -->

<script type="text/javascript">
    document.addEventListener("DOMContentLoaded", ready);
    function ready() {
        let member_btn = document.querySelector(".gh-subscribe-btn");
        if(member_btn) {
            let subscribe_modal = document.querySelector(".gh-subscribe");
            subscribe_modal.remove();
        }
    }
</script>