Revert image name back to quantecon_ubuntu2404

Author: mmcky

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ on:
         type: string
 jobs:
   preview:
-    runs-on: "runs-on=${{ github.run_id }}/family=g4dn.2xlarge/image=quantecon_lecture_build/disk=large"
+    runs-on: "runs-on=${{ github.run_id }}/family=g4dn.2xlarge/image=quantecon_ubuntu2404/disk=large"
     env:
       NETLIFY_AUTH_TOKEN: ${{ secrets.NETLIFY_AUTH_TOKEN }}
       NETLIFY_SITE_ID: ${{ secrets.NETLIFY_SITE_ID }}