fix(challenges): fix a test case in an Applied Accessibility

fix a test case in Applied Accessibility: Improve Accessibility of Audio Content with the audio
Element

challenges/01-responsive-web-design/applied-accessibility.json

@@ -521,7 +521,7 @@
           "text":
             "Make sure your <code>audio</code> element has a closing tag.",
           "testString":
-            "assert(code.match(/<\\/audio>/g) && code.match(/<audio controls>/g) && code.match(/<\\/audio>/g).length === code.match(/<audio controls>/g).length, 'Make sure your <code>audio</code> element has a closing tag.');"
+            "assert(code.match(/<\\/audio>/g).length === 1 && code.match(/<audio.*>[\\s\\S]*<\\/audio>/g), 'Make sure your <code>audio</code> element has a closing tag.');"
         },
         {
           "text":