Default enable new_graphql_keyset_pagination

Default enable the FF "new_graphql_keyset_pagination".

https://gitlab.com/gitlab-org/gitlab/-/issues/323730

A paginated graphql query may gain performance
if a keyset order can be automatically
built by the introduced changes behind the feature flag.

Changelog: performance

config/feature_flags/development/new_graphql_keyset_pagination.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/323730
 milestone: '13.10'
 type: development
 group: group::optimize
-default_enabled: false
+default_enabled: true

lib/gitlab/graphql/pagination/keyset/generic_keyset_pagination.rb

@@ -76,7 +76,7 @@ module Gitlab
 
           def items
             original_items = super
-            return original_items if Gitlab::Pagination::Keyset::Order.keyset_aware?(original_items) || Feature.disabled?(:new_graphql_keyset_pagination)
+            return original_items if Feature.disabled?(:new_graphql_keyset_pagination, default_enabled: :yaml) || Gitlab::Pagination::Keyset::Order.keyset_aware?(original_items)
 
             strong_memoize(:generic_keyset_pagination_items) do
               rebuilt_items_with_keyset_order, success = Gitlab::Pagination::Keyset::SimpleOrderBuilder.build(original_items)