Enable maven CTE query optimization FF

This commit enables the maven_metadata_by_path_with_optimization_fence
feature flag by default.

app/models/packages/package.rb

@@ -142,7 +142,7 @@ class Packages::Package < ApplicationRecord
   end
 
   def self.only_maven_packages_with_path(path, use_cte: false)
-    if use_cte && Feature.enabled?(:maven_metadata_by_path_with_optimization_fence)
+    if use_cte && Feature.enabled?(:maven_metadata_by_path_with_optimization_fence, default_enabled: :yaml)
       # This is an optimization fence which assumes that looking up the Metadatum record by path (globally)
       # and then filter down the packages (by project or by group and subgroups) will be cheaper than
       # looking up all packages within a project or group and filter them by path.

changelogs/unreleased/enable-maven-query-optimization-ff-by-default.yml

+---
+title: Optimize group level Maven package finder query
+merge_request: 57692
+author:
+type: performance

config/feature_flags/development/maven_metadata_by_path_with_optimization_fence.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/325460
 milestone: '13.11'
 type: development
 group: group::optimize
-default_enabled: false
+default_enabled: true