Fix NODES img path (neo4j#1385)

Updated page-ad-image to use base URI for path.

Author: recrwplay

publish.yml

@@ -56,7 +56,7 @@ asciidoc:
     # NODES 2025
     page-ad-overline-link: https://www.neo4j.com/nodes-2025?utm_source=docs&utm_medium=banner
     page-ad-overline: ''
-    page-ad-image: /assets/img/nodes-25.png
+    page-ad-image: "{neo4j-docs-base-uri}/assets/img/nodes-25.png"
     page-ad-icon: ''
     page-ad-title: Neo4j Online Developer Conference
     page-ad-description: Join us on November 6 for 24hrs of live and unique tech talks on graphs and AI