Duplicate blockonomics_data declaration causing checkout failure

[anktd]

This issue was reported on freshdesk tickets 338861 and 338857
The add_blockonomics_checkout_style function adds an inline script via add_action('wp_footer'):

    add_action('wp_footer', function() use ($additional_script) {
        printf('<script type="text/javascript">%s</script>', $additional_script);
    });

The script contains const blockonomics_data = '...'

Each time the shortcode [blockonomics_payment] executes, a new action is added to wp_footer. If the shortcode runs multiple times (could be due to themes, page builders, SEO plugins, caching), the script is output multiple times. Since const cannot be redeclared in JavaScript, this throws a SyntaxError. The error stops script execution, so the checkout container never initializes.