🐛 Fixed signup card in post plaintext and email preheader (#17163)

fixes https://github.com/TryGhost/Team/issues/3542

The signup card text was included in the post plaintext/excerpt and
email preheader

Author: SimonBackx

packages/html-to-plaintext/lib/html-to-plaintext.js

@@ -53,7 +53,9 @@ const loadConverters = () => {
             // Don't output hrs
             {selector: 'hr', format: 'skip'},
             // Don't output > in blockquotes
-            {selector: 'blockquote', format: 'block'}
+            {selector: 'blockquote', format: 'block'},
+            // Don't include signup cards in excerpts
+            {selector: '.kg-signup-card', format: 'skip'}
         ]
     });