Update cfp_link and remove reg_phrase

Updated conference details for Blastoff Rails.

Author: marcoroth

_data/conferences.yml

@@ -3272,10 +3272,9 @@
   url: https://blastoffrails.com
   twitter: blastoffrails
   announced_on: 2025-07-09
-  reg_phrase: "Registration Open"
   cfp_open_date: 2025-09-15
   cfp_close_date: 2026-01-10
-  cfp_link: https://www.papercall.io/cfps/6442/submissions/new
+  cfp_link: https://www.papercall.io/blastoff
 
 - name: Baltic Ruby 2026
   location: Hamburg, Germany