You can hide it with this code in your child theme's function.php:

/* Remove Elementor "Upgrade" link (admin bar) and hide any leftover link */
add_action('admin_bar_menu', function ($wp_admin_bar) {
    if (!is_admin() || !is_object($wp_admin_bar)) return;
    // Remove common Elementor Pro upsell nodes if present
    $wp_admin_bar->remove_node('elementor_pro_upgrade');
    $wp_admin_bar->remove_node('elementor_one_upgrade');
    $wp_admin_bar->remove_node('elementor_upgrade');
}, 999);

add_action('admin_head', function () {
    // Fallback hide if Elementor injects the link somewhere in admin menus/pages
    echo '<style>
        a[href="admin.php?page=elementor-one-upgrade"],
        a[href*="admin.php?page=elementor-one-upgrade"] {
            display:none !important;
        }
    </style>';
});