Enable `maven_packages_group_level_improvements` by default

app/finders/packages/maven/package_finder.rb

@@ -76,7 +76,7 @@ module Packages
 
       def group_level_improvements?
         strong_memoize(:group_level_improvements) do
-          Feature.enabled?(:maven_packages_group_level_improvements)
+          Feature.enabled?(:maven_packages_group_level_improvements, default_enabled: :yaml)
         end
       end
     end

app/models/packages/package.rb

@@ -138,7 +138,7 @@ class Packages::Package < ApplicationRecord
   after_commit :update_composer_cache, on: :destroy, if: -> { composer? }
 
   def self.for_projects(projects)
-    unless Feature.enabled?(:maven_packages_group_level_improvements)
+    unless Feature.enabled?(:maven_packages_group_level_improvements, default_enabled: :yaml)
       return none unless projects.any?
     end
 

changelogs/unreleased/326099-enabled-by-default.yml

+---
+title: Reduce the number of SQL queries executed on Maven file API endpoints
+merge_request: 59136
+author:
+type: performance

config/feature_flags/development/maven_packages_group_level_improvements.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/326099
 milestone: '13.11'
 type: development
 group: group::package
-default_enabled: false
+default_enabled: true

lib/api/maven_packages.rb

@@ -80,7 +80,7 @@ module API
 
       def fetch_package(file_name:, project: nil, group: nil)
         order_by_package_file = false
-        if Feature.enabled?(:maven_packages_group_level_improvements)
+        if Feature.enabled?(:maven_packages_group_level_improvements, default_enabled: :yaml)
           order_by_package_file = file_name.include?(::Packages::Maven::Metadata.filename) &&
                                     !params[:path].include?(::Packages::Maven::FindOrCreatePackageService::SNAPSHOT_TERM)
         end

spec/requests/api/maven_packages_spec.rb

@@ -387,7 +387,7 @@ RSpec.describe API::MavenPackages do
 
           subject
 
-          status = Feature.enabled?(:maven_packages_group_level_improvements) ? :not_found : :forbidden
+          status = Feature.enabled?(:maven_packages_group_level_improvements, default_enabled: :yaml) ? :not_found : :forbidden
           expect(response).to have_gitlab_http_status(status)
         end