User can add the same email address many times for subscribing

[ibugaj]

Current behavior

User can add the same email address many times for subscribing

Expected behavior

Notification, that email address has been added to subscribe before (because, I guess, that discount should be allowed only once time for the same address)

Steps to reproduce the issue

1. Scroll down page to Subscribe to the newsletter section
   2, Click on Subscribe button
2. On modal fill field by any email addressand click Subcribe
3. Repeat steps 2-3 (fill with the same email address)

Environment details

https://test.storefrontcloud.io/

[filrak]

i guess the mailchimp module is not working anyway @pkarw ?

[pkarw]

This behavior was intentional - we should just display some message from Mailchimp in case of re-entry or we can save the state to localStorage probably. This is not the Magento newsletter integration intentionally. I belive it should be saved in localStorage + we should handle the error message from mailchimp and that's all :)

[pkarw]

Related to #2754

[janmyszkier]

and possibly #1899