Allow to create pipelines in parent by default

This commit makes the FF enabled by default.

changelogs/unreleased/make-allow-to-run-in-parent-pipeline-by-default.yml

+---
+title: Allow to create merge request pipelines in target project when user has permission
+merge_request: 37322
+author:
+type: added

lib/gitlab/ci/features.rb

@@ -75,7 +75,7 @@ module Gitlab
       end
 
       def self.allow_to_create_merge_request_pipelines_in_target_project?(target_project)
-        ::Feature.enabled?(:ci_allow_to_create_merge_request_pipelines_in_target_project, target_project)
+        ::Feature.enabled?(:ci_allow_to_create_merge_request_pipelines_in_target_project, target_project, default_enabled: true)
       end
 
       def self.job_entry_matches_all_keys?