Docs: Fix nightly builds link (#73964)

* Fix nightly builds link

Replace dead link for nightly OSS builds

* Updated link

* Got updated link

* Fixed link properties

docs/sources/_index.md

@@ -44,7 +44,7 @@ title: Grafana documentation
         </div>
         <h5>Grafana Cloud</h5>
     </a>
-    <a href="https://grafana.com/grafana/nightly?edition=oss" class="nav-cards__item nav-cards__item--install">
+    <a href="https://grafana.com/grafana/download/nightly?edition=oss" class="nav-cards__item nav-cards__item--install">
         <div class="nav-cards__icon fa fa-moon-o">
         </div>
         <h5>Nightly builds</h5>