test: titles in project previews (#45051)

* fix: trim titles before injecting into iframes

Surrounding whitespace isn't useful

* test: check preview iframe has correct title

client/src/templates/Challenges/utils/build.js

@@ -213,7 +213,9 @@ export function updateProjectPreview(buildData, document) {
     const titleMatch = buildData?.sources?.index?.match(
       /<title>(.*?)<\/title>/
     );
-    const frameTitle = titleMatch ? titleMatch[1] + ' preview' : 'preview';
+    const frameTitle = titleMatch
+      ? titleMatch[1].trim() + ' preview'
+      : 'preview';
     createProjectPreviewFramer(document, frameTitle)(buildData);
   } else {
     throw new Error(