remove stale changelog entry (#84187)

* forward-port of a fix that was already included in 2.17.0 and backported to all supported stable branches

changelogs/fragments/cve-2023-5764.yml

@@ -1,6 +0,0 @@
-security_fixes:
-- templating - Address issues where internal templating can cause unsafe
-  variables to lose their unsafe designation (CVE-2023-5764)
-breaking_changes:
-- assert - Nested templating may result in an inability for the conditional
-  to be evaluated. See the porting guide for more information.