Remove the longer_count_cache_validity_period feature flag

app/models/user.rb

@@ -1620,11 +1620,7 @@ class User < ApplicationRecord
   end
 
   def count_cache_validity_period
-    if Feature.enabled?(:longer_count_cache_validity, self, default_enabled: :yaml)
     24.hours
-    else
-      20.minutes
-    end
   end
 
   def assigned_open_merge_requests_count(force: false)

changelogs/unreleased/remove-longer-count-cache-validity-ff.yml

+---
+title: Remove the longer_count_cache_validity_period feature flag
+merge_request: 59746
+author:
+type: performance

config/feature_flags/development/longer_count_cache_validity.yml

----
-name: longer_count_cache_validity
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/57122
-rollout_issue_url: 
-milestone: '13.11'
-type: development
-group: group::source code
-default_enabled: false