fix: restore conclusion page for Pinocchio Escrow

File originally removed in commit 2e69834

Author: dhl

src/app/content/challenges/pinocchio-escrow/en/pages/conclusion.mdx

@@ -0,0 +1,13 @@
+# Conclusion
+
+You can now test your program against our unit tests and claim your NFTs!
+
+Start by building your program using the following command in your terminal:
+
+```
+cargo build-sbf
+```
+
+This generated a `.so` file directly in your `target/deploy` folder.
+
+Now click on the `take challenge` button and drop the file there!