Shorten Welcome Message fix

We want to ignore certain tags when they show up in the HTML.
This now ignores script tags and link tags (for stylesheets)

common/static/common/js/utils/clamp-html.js

@@ -12,6 +12,10 @@
 function clampHtmlByWords(root, wordsLeft) {
     'use strict';
 
+    if (root.nodeName === 'SCRIPT' || root.nodeName === 'LINK') {
+        return wordsLeft; // early exit and ignore
+    }
+
     var remaining = wordsLeft;
     var nodes = Array.from(root.childNodes ? root.childNodes : []);
     var words, chopped;

common/static/common/js/utils/clamp-html.test.jsx

@@ -3,6 +3,8 @@ import ReactDOM from 'react-dom';
 import { clampHtmlByWords } from './clamp-html';
 
 let container;
+const scriptTag = '<script src="/asset-v1:edX+testX+1T2021+type@asset+block/script.js"></script>';
+const stylesheet = '<link rel="stylesheet" type="text/css" href="/asset-v1:edX+testX+1T2021+type@asset+block/introjs.css">';
 
 beforeEach(() => {
   container = document.createElement("div");
@@ -25,6 +27,9 @@ describe('ClampHtml', () => {
     ['a <i>aa <em>aaa</em></i>', 2, 'a <i>aa…</i>'],
     ['a <i>aa <em>aaa</em> ab</i>', 3, 'a <i>aa <em>aaa…</em></i>'],
     ['a <i>aa ab</i> b c', 4, 'a <i>aa ab</i> b…'],
+    [scriptTag + 'a b c', 2, scriptTag + 'a b…'],
+    [stylesheet + 'a b c', 2, stylesheet + 'a b…'],
+    [scriptTag + stylesheet + 'a b c', 2, scriptTag + stylesheet + 'a b…'],
   ])('clamps by words: %s, %i', (input, wordsLeft, expected) => {
     const div = ReactDOM.render(<div dangerouslySetInnerHTML={{ __html: input }} />, container);
     clampHtmlByWords(div, wordsLeft);