fix(curriculum/client): runtime error (#63509)

client/src/templates/Introduction/components/block.tsx

@@ -543,7 +543,7 @@ export class Block extends Component<BlockProps> {
           isExpanded={isExpanded}
           percentageCompleted={percentageCompleted}
           accordion={accordion}
-          blockUrl={challenges[0].fields.slug}
+          blockUrl={challenges?.[0]?.fields?.slug ?? ''}
         />
       </>
     );

curriculum/structure/blocks/workshop-string-inspector.json

@@ -1,6 +1,6 @@
 {
   "name": "Build a String Inspector",
-  "isUpcomingChange": true,
+  "isUpcomingChange": false,
   "dashedName": "workshop-string-inspector",
   "helpCategory": "JavaScript",
   "blockLayout": "challenge-grid",