Remove usage_data_track_quickactions feature flag traces

- Remove yml file
- Remove flag from know events
- Remove conditional

changelogs/unreleased/321054-remove-feature-flag-code-quick-actions.yml

+---
+title: Remove usage_data_track_quickactions feature flag
+merge_request: 59914
+author:
+type: other

config/feature_flags/development/usage_data_track_quickactions.yml

----
-name: usage_data_track_quickactions
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/52398
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/321054
-milestone: '13.9'
-type: development
-group: group::project management
-default_enabled: true

lib/gitlab/usage_data_counters/quick_action_activity_unique_counter.rb

@@ -7,7 +7,6 @@ module Gitlab
         # Tracks the quick action with name `name`.
         # `args` is expected to be a single string, will be split internally when necessary.
         def track_unique_action(name, args:, user:)
-          return unless Feature.enabled?(:usage_data_track_quickactions, default_enabled: :yaml)
           return unless user
 
           args ||= ''