Enable new_project_level_vsa_backend FF by default

app/models/cycle_analytics/level_base.rb

@@ -60,7 +60,7 @@ module CycleAnalytics
     end
 
     def [](stage_name)
-      if Feature.enabled?(:new_project_level_vsa_backend, resource_parent)
+      if Feature.enabled?(:new_project_level_vsa_backend, resource_parent, default_enabled: true)
         StageAdapter.new(build_stage(stage_name), options)
       else
         Gitlab::CycleAnalytics::Stage[stage_name].new(options: options)

changelogs/unreleased/enable-new_project_level_vsa_backend-by-default.yml

+---
+title: Use the improved version of Value Stream Analytics backend on the project level
+merge_request: 50141
+author:
+type: performance

config/feature_flags/development/new_project_level_vsa_backend.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/282435
 milestone: '13.7'
 type: development
 group: group::optimize
-default_enabled: false
+default_enabled: true