chore: update conference data

- Update conference entries in conferences.yml
- Sync utils/conferences tracking file

Author: JesperDramsch

_data/conferences.yml

@@ -199,7 +199,7 @@
     longitude: 174.7772114
 
 - conference: Wagtail Space
-  year: 2024
+  year: 2025
   link: https://wagtail.org/wagtail-space-2025/
   cfp_link: https://pretalx.com/wagtail-space-2025/cfp
   cfp: '2025-08-15 23:59:00'