Fix Pages deploy failure by reverting broken Umami asset update

[Copilot]

The pages build and deployment workflow started failing in the deploy job right after the Umami script update. This change rolls back that asset swap to restore the last known-good deployable site artifact.

• Root-cause-aligned rollback

  • Reverted index.html to reference the previously deployed Umami script and matching SRI hash.
  • Removed the newly added js/um.1783060599.js file introduced by the failing update.

• Scope

  • Limited to the Umami script reference and corresponding JS asset only.
  • No unrelated content, styling, or site structure changes.

<!-- reverted to prior known-good asset -->
<script
  defer
  src="js/um.1779783938.js"
  data-website-id="04990c3f-8bee-4fe5-82a2-f5786067ce80"
  data-host-url="https://api-gateway.umami.dev"
  data-domains="pescara.python.it"
  integrity="sha512-Ase1UXdmVNlzlziUFISZVirXrLH70K9ArSABHgv0YusRduuH/9Er9KZrJ2Da8MimDyeVHBuCZevYt3rHkjJmXw=="
></script>