Comment by stillkicking

This injected CSS will remove the popup:

    body article.newsletter-post.post .subscribe-dialog,
    body article.newsletter-post.post .subscribe-dialog-scroll-modal-scroll-capture { display: none !important; }

Isn't it sad how phones have normalized the idea that you no longer have control over the webpages you read? It's not like this was even necessary, it's the exact same browser, just with a dumber front-end.