Subscription option on Newsletter Sign up modal

🔍 Problem Statement
As a publisher, I experience the newsletter sign-up modal having no subscription CTA, which misses the opportunity to convert newly registered readers into paid subscribers while they are engaged.

💡 User Story
As a reader who just signed up for a newsletter, I want to see a "Subscribe Now" option immediately after, so that I can easily upgrade to a paid subscription in the same flow.

🎯 Definition of Done
- Given the newsletter sign-up modal, when a user completes registration, then a "Subscribe Now" CTA is displayed as a configurable next step.
- This change impacts the JS-SDK / ReactJS Elements (newsletter modal component).
- Limitations: CTA is optional and publisher-configurable; it does not block newsletter confirmation.

In the Pelcro out of the box UI, the current newsletter sign up modal that provides extra articles when a reader signs up doesn’t contain a subscribe now CTA. I would suggest adding one. I have attached two examples. Adding this could help convert to a subscriber faster.