Update deleteSite response to include success status

- Modified the response of the deleteSite function to return a success message in the response body, enhancing clarity for the client regarding the operation's outcome.

server/src/api/sites/deleteSite.ts

@@ -30,5 +30,5 @@ export async function deleteSite(
   // Remove the site from the siteConfig cache
   siteConfig.removeSite(Number(id));
 
-  return reply.status(200).send();
+  return reply.status(200).send({ success: true });
 }