Clean up self-approve test workflow and CHANGELOG marker (#2978)

Made-with: Cursor

Author: edsavage

.github/workflows/test-self-approve.yml

@@ -7,8 +7,6 @@
 
 = Elasticsearch Release Notes
 
-// Test self-approve — unique marker 2026-03-08T23:00Z
-
 //
 // To add a release, copy and paste the following text,  uncomment the relevant
 // sections, and add a link to the new section in the list of releases at the