Variable entity_id is undefined in /recurly/modules/recurlyjs/src/Form/RecurlyJsSubscribeForm.php (line 88)

Issue Description

The variable $entity_id is never defined on line 88 in /recurly/modules/recurlyjs/src/Form/RecurlyJsSubscribeForm.php

As a result, the account code is always 'user-' which causes issues with multiple account creation via the Subscribe form.
$recurly_account->account_code = $entity_type . '-' . $entity_id;

Solution/Patch

A simple patch replacing $entity_id with $entity->id() should resolve this issue.